JPWO2010113475A1 - Mask blank and transfer mask - Google Patents

Abstract

[Problem] A mask blank and a transfer material that have a sufficient improvement effect and are practical for the problem of the electromagnetic field (EMF) effect, which is a problem in the generation of DRAM half pitch (hp) 32 nm or later in the semiconductor design rule. Provide a mask. [Solution] A mask blank used for producing a transfer mask to which ArF exposure light is applied, and is formed from a laminated structure of a light shielding layer 11 and a surface antireflection layer 12 formed on a translucent substrate 1. A light shielding film 10 and an auxiliary light shielding film 20 formed above the light shielding film 10. The light shielding film 10 has a film thickness of 40 nm or less and an optical density of 2.0 or more and 2.7 or less. The optical density in the laminated structure of the light shielding film 10 and the auxiliary light shielding film 20 is 2.8 or more.

Description

  The present invention relates to a mask blank, a transfer mask, and the like used in manufacturing a semiconductor device and the like.

Miniaturization of semiconductor devices and the like has an advantage of improving performance and functions (high-speed operation, low power consumption, etc.) and cost reduction, and miniaturization is increasingly accelerated. Lithography technology supports this miniaturization, and a transfer mask is a key technology along with an exposure apparatus and a resist material.
In recent years, development of the DRAM half pitch (hp) 45 nm to 32 nm generation, which is a design specification of semiconductor devices, has been promoted. This corresponds to 1/4 to 1/6 of the wavelength 193 nm of ArF excimer laser exposure light (hereinafter referred to as ArF exposure light). Especially in the generations after hp45nm, only application of conventional phase shift method, oblique incidence illumination method and pupil filter method such as super-resolution technology (Resolution Enhancement Technology: RET) and optical proximity effect correction (Optical Proximity Correction: OPC) technology. It has become inadequate, and ultra-high NA technology (immersion lithography) has become necessary.

By the way, circuit patterns necessary for semiconductor manufacture are sequentially exposed on a semiconductor wafer by a plurality of photomask (reticle) patterns. For example, a reduction projection exposure apparatus (exposure apparatus) on which a predetermined reticle is set projects and exposes a pattern repeatedly while shifting the projection area on the wafer one after another (step-and-repeat method), or the reticle and wafer. Are scanned with respect to the projection optical system, and a repeated pattern is projected and exposed (step-and-scan method). As a result, a predetermined number of integrated circuit chip regions are formed in the semiconductor wafer.
The photomask (reticle) has an area where a transfer pattern is formed and an area around the area. This peripheral area, that is, the peripheral area along the four sides of the photomask (reticle) is integrated when the transfer pattern on the photomask (reticle) is sequentially exposed while sequentially shifting the projected areas on the wafer. In order to increase the number of circuit chips formed, exposure and transfer are performed so that the outer peripheral regions overlap each other. Usually, the mask stage of the exposure apparatus is provided with a shielding plate for shielding exposure light to the outer peripheral region. However, the shielding of the exposure light by the shielding plate poses problems of positional accuracy limitations and light diffraction phenomenon, and it is inevitable that the exposure light leaks to the outer peripheral area (this light is referred to as leakage light). If the leakage light to the outer peripheral region passes through the photomask, the resist on the wafer may be exposed. For the purpose of preventing resist exposure on the wafer due to such overexposure, a light-shielding band (light-shielding body band, light-shielding body ring) is produced by mask processing in the outer peripheral region of the photomask. In addition, in the area where the light shielding band is formed in the outer peripheral area, it is generally desirable that the OD value (optical density) is 3 or more in order to suppress resist exposure on the wafer due to overexposure, and at least 2 About 8 is required.

In the case of a binary mask, since the light shielding film has a high light shielding property, the light shielding film has a role of forming a light shielding film pattern in the transfer pattern region and also forming a light shielding band in an outer peripheral region of the transfer pattern region.
When the light shielding film is made thinner, the OD value (optical density) decreases. A chromium-based light-shielding film requires a total film thickness of about 60 nm in order to achieve OD = 3, which is generally required, and it is difficult to reduce the thickness significantly (for example, Patent Document 1). [Refer to [0005] column).
Further, for example, it is necessary even in the case of a so-called binary photomask having a light shielding film having a laminated structure of MoSi-based materials, for example, a light shielding film having a laminated structure of MoSiN main light shielding layer / MoSiON antireflection layer from the substrate side. In order to achieve OD = 2.8, the total film thickness of about 60 nm is usually the minimum required, and it is difficult to make a significant thin film (Patent Document 2).

  On the other hand, there is a limit to producing a fine and high-density transfer pattern on a single transfer mask. A double patterning / double exposure technique has been developed as one of means for solving the problems of the lithography technique. In both double pattern / double exposure technologies, one fine and high-density transfer pattern is divided into two relatively sparse patterns (first pattern and second pattern), and the two patterns A transfer mask is prepared for each of the above. This is a lithography technique in which a fine and high-density transfer pattern is transferred to a resist on a wafer using the two-sheet transfer mask.

JP 2007-241136 A JP 2006-78825 A

  By the way, in the generation of binary masks of DRAM half pitch (hp) 32 nm or later in the design specifications of semiconductor devices, the line width of the transfer pattern on the transfer mask is smaller than the wavelength of 193 nm of ArF exposure light. As a result of adopting super-resolution technology to cope with this, if the thickness of the light-shielding film pattern in the transfer pattern area (main pattern area) is large, the bias caused by the electromagnetic field (EMF) effect Has become a problem. The bias related to the electromagnetic field (EMF) effect greatly affects the CD accuracy of the transfer pattern line width to the resist on the wafer. For this reason, it is necessary to perform a simulation of an electromagnetic field effect and to correct a transfer pattern produced on a transfer mask for suppressing the influence of an EMF bias. This transfer pattern correction calculation becomes more complicated as the EMF bias increases. Also, the corrected transfer pattern becomes more complex as the EMF bias increases, and a larger load is imposed on the transfer mask fabrication. These new challenges have arisen as the bias due to EMF increases.

  On the other hand, by using the double patterning / double exposure technique, the line width of the transfer pattern formed on one transfer mask becomes relatively wide, so that the problem caused by the electromagnetic field effect is less likely to occur. However, particularly in the case of the double exposure technique, the same resist on the wafer is exposed twice with two transfer masks. In exposure on a resist on a wafer using a single transfer mask in a conventional reduction projection exposure apparatus (this is called single exposure), overlapping exposure on the wafer due to light leaking to the outer peripheral area of the transfer pattern In the portion, the exposure is performed up to four times. Therefore, it is sufficient if the light shielding band can secure an optical density sufficient to prevent the resist on the wafer from being exposed to light even when a small amount of exposure light passing through the light shielding band is exposed four times. On the other hand, when the double exposure technique is used, since the exposure is performed twice with two transfer masks, the overlapping exposure portion on the wafer is exposed a maximum of eight times. For this reason, the transfer mask used in the double exposure technique needs to have a light-shielding band that secures an optical density sufficient to prevent the resist on the wafer from being exposed to light even when the exposure light transmitted through the light-shielding band is exposed eight times. . The optical density necessary for the light-shielding band is considered to be at least 3.1.

  In order to ensure an optical density of 3.1 or more, it is necessary to make the thickness of the light shielding film thicker than before. The double exposure technology is a technology that realizes the line width of the transfer pattern, which was difficult in the past, so even if it is divided into two relatively sparse transfer patterns, the transfer pattern line width does not have much room. Absent. If the thickness of the light-shielding film is thicker than before, the influence of the electromagnetic field effect cannot be neglected. Even if the optical density required for the shading band used in the double exposure technology can be secured with the same film thickness as before, it is expected that the transfer pattern will continue to become finer and more dense. Therefore, even with the transfer pattern line width divided into two, it is easily expected that the same problem as the influence of the electromagnetic field effect which is a problem in the current transfer mask for single exposure will occur.

  Optical simulations in binary mask design are based on the shape of correction patterns such as OPC and SRAF that should be additionally placed so that the designed transfer pattern can be exposed and transferred onto the transfer object (resist on the wafer) as designed. The main purpose is to calculate the correction amount (bias amount) of the pattern line width. An optical simulation of this mask design is TMA (Thin Mask Analysis). TMA calculates the correction pattern shape and the correction amount of the pattern line width as an ideal film in which the light shielding film of the transfer mask has a predetermined optical density with a film thickness of zero. Since this is a simple simulation performed with an ideal film, there is a great merit that the calculation load of the simulation is small. However, since the simulation does not consider the EMF effect, the TMA simulation result alone is not sufficient for the recent fine pattern in which the influence of the EMF effect becomes large.

The inventors of the present invention have intensively developed the above-mentioned problem of the electromagnetic field (EMF) effect.
First, we focused on the fact that a light-shielding film that is less affected by the EMF effect makes it easier to use TMA simulations and can reduce the load of EMF bias correction calculation. Furthermore, as a result of research on a light-shielding film having a small influence of the EMF effect, it was found by simulation that a remarkable improvement effect is recognized in reducing the EMF bias when the thickness of the light-shielding film in the binary mask is 40 nm or less. That is, when the thickness of the light-shielding film is 40 nm or less, the transfer pattern correction calculation load for correcting the influence of the EMF bias decreases, and the transfer mask manufacturing load also decreases. Furthermore, it has been found by simulation that the EMF bias can be significantly reduced when the thickness of the light shielding film is 35 nm or less. However, even if a metal silicide-based (MoSi-based, WSi, etc.) material that is considered to be a material having a high optical density compared with the same film thickness is selected, the condition that the optical density is 2.8 and the film thickness is 40 nm or less It turns out that it is not easy to meet. Furthermore, a material having a high optical density such as a metal silicide material has a high reflectance with respect to exposure light. The light-shielding film needs to have a low reflectivity with respect to the exposure light on the surface where the light-shielding film is exposed as a transfer pattern after fabrication of the transfer mask, with a predetermined value or less (for example, 40% or less). In order to realize a thin film, the light shielding film needs to have at least a two-layer structure of a light shielding layer and a surface antireflection layer. Since the surface antireflection layer needs to secure a certain degree of transmittance in order to reduce surface reflection, it cannot contribute much in terms of optical density.

  The inventors of the present invention have an optical density of 2.8 or more, which is conventionally required for a light shielding film of a binary transfer mask, 30% or less, which is a desirable surface reflectance with respect to exposure light, and a film thickness of 40 nm. The feasibility of the following light-shielding film was verified through experiments and simulations. As a result, it has been found that it is difficult to satisfy all the conditions with existing film materials. However, if the lower limit value of the optical density of the light-shielding film can be lowered (for example, 2.0 or more) compared to the conventional case, it is 30% or less, which is a desirable surface reflectance for exposure light, and the film thickness is 40 nm. It was also found that the following light shielding film is feasible. However, when the optical density of the light shielding film of the binary transfer mask is lowered, when this transfer mask is used for exposure transfer to the transfer target (resist on the wafer, etc.), Until now, it has not been verified whether sufficient contrast comparable to that can be obtained. This is because in the conventional binary transfer mask, there is not much need for a light-shielding film that is so thin that the OD must be lowered, and considering the mask manufacturing process, the light-shielding film that forms the transfer pattern is shielded from light. It may be the simplest to use as it is for the formation of the belt. The present inventors also conducted experiments and simulations on this point, and found that even if the lower limit value of the optical density was lowered as compared with the conventional case, a comparable contrast could be obtained.

The present invention is a mask which has a sufficient improvement effect and a practicality for the problem of the electromagnetic field (EMF) effect which becomes a problem in the generation of DRAM half pitch (hp) 32 nm or later, which is a design specification of a semiconductor device. An object is to provide a blank and a transfer mask.
The present inventors have addressed the problem of the electromagnetic field (EMF) effect, which is a problem in the generation after DRAM half pitch (hp) 32 nm, which is a design specification of a semiconductor device.
A light shielding film for forming a transfer pattern in the transfer pattern area and an auxiliary light shielding film for assisting formation of a light shielding band (light shielding ring) in the outer peripheral area of the transfer pattern area (the auxiliary light shielding film is not formed in the transfer pattern area) ) With a thin film,
The light-shielding film for forming the transfer pattern in the transfer pattern region is formed of a thin film having a film thickness that can sufficiently satisfy the above-mentioned problem and satisfy the required level and an optical density necessary for transfer. It was found that it could be improved sufficiently to achieve (realize) the required level.

  In addition to the above, in the outer peripheral region of the transfer pattern region, the auxiliary light shielding film is a laminate with the light shielding film and has a light shielding band having a sufficient optical density (for example, 2.8 or more, preferably 3.0 or more). It was found that a light-shielding ring) can be formed and practicality can be secured, and the present invention has been completed.

The present invention has the following configuration.
(Configuration 1)
A mask blank used for producing a transfer mask to which ArF exposure light is applied,
A light shielding film having a laminated structure of a light shielding layer and a surface antireflection layer formed on a light transmissive substrate, and an auxiliary light shielding film formed above the light shielding film,
The light shielding film has a film thickness of 40 nm or less and an optical density with respect to exposure light of 2.0 or more and 2.7 or less,
The light shielding layer has a thickness of 15 nm or more and 35 nm or less,
A mask blank having an optical density of 2.8 or more with respect to exposure light in a laminated structure of the light shielding film and the auxiliary light shielding film.
(Configuration 2)
2. The mask blank according to Configuration 1, wherein the surface antireflection layer has a film thickness of 5 nm or more and 20 nm or less, and a surface reflectance for exposure light of 30% or less.
(Configuration 3)
3. The mask blank according to claim 1, wherein an optical density with respect to exposure light in the laminated structure of the light shielding film and the auxiliary light shielding film is 3.1 or more.
(Configuration 4)
4. The mask blank according to any one of configurations 1 to 3, wherein the light shielding layer contains 90% or more of transition metal silicide.
(Configuration 5)
The mask blank according to Configuration 4, wherein the transition metal silicide in the light shielding layer is molybdenum silicide, and the molybdenum content is 9 atomic% or more and 40 atomic% or less.
(Configuration 6)
6. The mask blank according to any one of configurations 1 to 5, wherein the surface antireflection layer is made of a material containing transition metal silicide as a main component.
(Configuration 7)
The mask blank according to any one of Structures 1 to 6, wherein the auxiliary light shielding film has resistance to an etching gas used when etching the light shielding film.
(Configuration 8)
The auxiliary light-shielding film contains at least one of nitrogen and oxygen in chromium, the chromium content in the film is 50 atomic% or less, and the film thickness is 20 nm or more. The mask blank according to any one of configurations 1 to 7.
(Configuration 9)
A transfer mask produced using the mask blank according to any one of Configurations 1 to 8.

  According to the present invention, lithography for applying ArF exposure light when producing a transfer mask has become prominent in generations after DRAM half pitch (hp) 32 nm, which is a semiconductor device design specification. Minimum optical density required to form a light-shielding film that needs to be thinned in order to solve various problems related to the electromagnetic field (EMF) effect, and a transfer pattern on the transfer target (resist on the wafer, etc.) In order to secure the required optical density by the laminated structure of the light shielding film and the auxiliary light shielding film, the light shielding band necessary for reducing the influence of the leakage light due to the overexposure can be secured. It is possible to provide a mask blank and a transfer mask capable of achieving both the resolution of various problems related to the EMF) effect and the problem related to the leakage light caused by the overexposure.

FIG. 1 is a schematic cross section showing a first embodiment of a mask blank of the present invention. FIG. 2 is a schematic cross section showing a second embodiment of the mask blank of the present invention. FIG. 3 is a schematic cross section showing a third embodiment of the mask blank of the present invention. FIG. 4 is a schematic cross section showing a fourth embodiment of the mask blank of the present invention. FIG. 5 is a schematic cross-sectional view showing a fifth embodiment of the mask blank of the present invention. FIG. 6 is a diagram showing the relationship between the molybdenum content and the optical density per unit film thickness in a thin film made of molybdenum silicide metal. FIG. 7 is a diagram for explaining modes in forming an etching mask film. FIG. 8 is a schematic cross-sectional view for explaining a manufacturing process of a transfer mask according to an embodiment of the present invention. FIG. 9 is a schematic cross-sectional view for explaining a manufacturing process of a transfer mask according to another embodiment of the present invention. FIG. 10 is a schematic cross-sectional view for explaining a manufacturing process of a transfer mask according to still another embodiment of the present invention. FIG. 11 is a schematic cross-sectional view for explaining a manufacturing process of a transfer mask according to still another embodiment of the present invention. FIG. 12 is a schematic cross-sectional view for explaining a manufacturing process of a transfer mask according to still another embodiment of the present invention. FIG. 13: is a figure which shows the result of having calculated the optical density and surface reflectance in each film thickness of the light shielding film and surface reflection preventing layer which concern on Example 4-1 of this invention with the optical simulation. FIG. 14 is a diagram illustrating a result of calculating the relationship between the optical density and the contrast of the light shielding film according to Example 4-1 of the present invention by optical simulation. FIG. 15 is a diagram illustrating a result of calculating the EMF bias at each film thickness of the light shielding film according to Example 4-1 of the present invention by optical simulation. FIG. 16 is a diagram illustrating a result of calculating optical density and surface reflectance at each film thickness of the light shielding film and the surface antireflection layer according to Example 4-2 of the present invention by optical simulation. FIG. 17 is a diagram illustrating the result of calculating the relationship between the optical density and contrast of the light shielding film according to Example 4-2 of the present invention by optical simulation. FIG. 18 is a diagram illustrating a result of calculating the EMF bias at each film thickness of the light shielding film according to Example 4-2 of the present invention by optical simulation. FIG. 19 is a diagram illustrating a result of optical density and surface reflectance calculated for each film thickness of the light shielding film and the surface antireflection layer according to Example 4-3 of the present invention by optical simulation. FIG. 20 is a diagram illustrating a result of calculating the relationship between the optical density and contrast of the light shielding film according to Example 4-3 of the present invention by optical simulation. FIG. 21 is a diagram illustrating a result of calculating an EMF bias at each film thickness of the light shielding film according to Example 4-3 of the present invention by optical simulation. FIG. 22 is a diagram illustrating a result of optical density and surface reflectance calculated for each film thickness of the light shielding film and the surface antireflection layer according to Example 6-1 of the present invention by optical simulation. FIG. 23 is a diagram illustrating a result of calculating the EMF bias at each film thickness of the light shielding film according to Example 6-1 of the present invention by optical simulation. FIG. 24 is a diagram illustrating a result of optical density and surface reflectance calculated for each film thickness of the light shielding film and the surface antireflection layer according to Example 6-2 of the present invention by optical simulation. FIG. 25 is a diagram illustrating a result of calculating the relationship between the optical density and contrast of the light shielding film according to Example 6-2 of the present invention by optical simulation. FIG. 26 is a diagram illustrating a result of calculating the EMF bias at each film thickness of the light shielding film according to Example 6-2 of the present invention by optical simulation.

Hereinafter, the present invention will be described in detail.
The mask blank of the present invention is a mask blank used for producing a transfer mask to which ArF exposure light is applied, and has a laminated structure of a light shielding layer and a surface antireflection layer formed on a translucent substrate. A light shielding film and an auxiliary light shielding film formed above the light shielding film. The light shielding film has a thickness of 40 nm or less and an optical density with respect to exposure light of 2.0 or more and 2.7 or less. The light shielding layer has a film thickness of 15 nm or more and 35 nm or less, and an optical density with respect to exposure light in a laminated structure of the light shielding film and the auxiliary light shielding film is 2.8 or more.
In the mask blank of the present invention, the surface antireflection layer preferably has a film thickness of 5 nm or more and 20 nm or less and a surface reflectance of 30% or less for exposure light.
With such a configuration, the semiconductor device has a sufficient improvement effect on the electromagnetic field effect (EMF) problem that will be a problem in the generation of DRAM half pitch (hp) 32 nm or later, which is a design specification of a semiconductor device. It is possible to provide a mask blank and a transfer mask that have a sufficient effect on the problem of leakage light in overexposure.

  For example, as shown in FIG. 1, the mask blank of the present invention is formed on a light-transmitting substrate 1 above a light shielding film 10 having a laminated structure of a light shielding layer 11 and a surface antireflection layer 12 and above the light shielding film 10. The auxiliary light shielding film 20 and the resist film 100 are provided.

In the present invention, the light shielding film 10 is a lithography to which ArF exposure light is applied, and improves the problem of the electromagnetic field (EMF) effect, which becomes a problem in the generation after DRAM half pitch (hp) 32 nm, and meets the required level. It is a film having both a film thickness and an optical density that can be satisfied. At this time, the film thickness and optical density of the light-shielding film 10 are considered in consideration of the contribution to the problem improvement of the electromagnetic field (EMF) effect by reducing the film thickness and the influence on the transfer by reducing the optical density. It is important to determine
Considering the contribution to improving the problem of the electromagnetic field (EMF) effect by reducing the film thickness and giving the necessary optical density to the transfer pattern region, the upper limit of the film thickness of the light shielding film 10 is 40 nm or less. Is desirable.
Considering the contribution to improving the problem of the electromagnetic field (EMF) effect by reducing the film thickness, the thickness of the light shielding film 10 is preferably 35 nm or less, and more preferably 30 nm or less.
Considering the effect on transfer by lowering the optical density, the lower limit of the optical density of the light shielding film 10 is preferably 2.0 or more, and preferably 2.3 (transmittance 0.05%) or more.
Since the optical density of the light shielding film 10 increases as the film thickness increases (the optical density is approximately proportional to the film thickness), the optical density of the light shielding film 10 is independent regardless of the film thickness. Cannot be set. That is, the request to reduce the film thickness and the request to increase the optical density are contradictory. The optical density of the light-shielding film 10 is preferably higher if the film thickness is the same. However, priority is given to the contribution to the improvement of the electromagnetic field (EMF) effect by reducing the film thickness, and the optical density is barely limited. From the viewpoint of suppressing the optical density, the optical density of the light shielding film 10 is preferably 2.7 or less, more preferably 2.5 or less, and further preferably 2.3 or less.

The optical density of the entire light shielding film 10 is almost contributed by the light shielding layer 11. The surface antireflection layer 12 is provided in order to prevent a part of the exposure light reflected by the lens of the reduction optical system of the exposure apparatus from being further reflected by the light shielding film 10. It is adjusted to transmit to some extent. Thereby, the total reflection on the surface of the light shielding film 10 is suppressed, and the exposure light can be attenuated by utilizing the interference effect. Since the surface antireflection layer 12 is designed to obtain this predetermined transmittance, the contribution of the optical density to the entire light shielding film 10 is small. From the above, the adjustment of the optical density of the light shielding film 10 is basically performed by the light shielding layer 11. That is, it is desirable that the light shielding layer 11 can ensure an optical density of 2.0 or more.
As the surface reflectance of the light shielding film 10 with respect to ArF exposure light, it is highly necessary to secure 40% or less, preferably 30% or less, more preferably 25% or less, and the entire thickness of the light shielding film 1 is reduced. If it is within the allowable range, it is most preferable that 20% or less can be secured.
Further, in order to suppress the surface reflectance to a predetermined value (30%) or less, it is highly necessary that the film thickness of the surface antireflection layer 12 is 5 nm or more, and to suppress the surface reflectance to 25% or less. It is desirable to be larger than 5 nm. In order to obtain a lower reflectance (20% or less), the film thickness is desirably 7 nm or more. Further, considering the production stability and the reduction in the thickness of the surface antireflection layer 12 due to repeated mask cleaning after the transfer mask is produced, the thickness of the surface antireflection layer 12 is preferably 10 nm or more. Further, the surface antireflection layer 12 preferably has a layer thickness of 20 nm or less, and more preferably 17 nm or less. In consideration of thinning of the entire light shielding film 10, the thickness is most preferably 15 nm or less.

  In the present invention, the auxiliary light shielding film 20 needs to ensure a light shielding property of at least an optical density of 2.8 or more in a laminated structure with the light shielding film 10. For example, when the light shielding film 10 has an optical density of 2.0, the auxiliary light shielding film 20 needs to have an optical density of 0.8 or more. This is because, in the light shielding zone, together with the optical density of the light shielding film 10, a light shielding property with an optical density of 2.8 or more is ensured.

FIG. 1 shows an example of a mask blank according to the first embodiment of the present invention.
In the first embodiment, as shown in FIG. 1, a light shielding film 10 having a laminated structure of a light shielding layer 11 and a surface antireflection layer 12 on an optically transparent substrate 1, and an auxiliary formed on the light shielding film 10. A light shielding film 20 and a resist film 100 are provided.

FIG. 2 shows an example of a mask blank according to the second embodiment of the present invention.
In the second embodiment, as shown in FIG. 2, a light shielding film 10 having a laminated structure of a light shielding layer 11 and a surface antireflection layer 12 on an optically transparent substrate 1, and an auxiliary formed on the light shielding film 10. The light shielding film 20, the etching mask film (also referred to as a hard mask, hereinafter the same) 30 formed on the auxiliary light shielding film 20, the adhesion improving layer 60 formed on the etching mask film 30, and the resist film 100 Have

FIG. 3 shows an example of a mask blank according to the third embodiment of the present invention.
In the third embodiment, as shown in FIG. 3, a light shielding film 10 having a laminated structure of a light shielding layer 11 and a surface antireflection layer 12 on an optically transparent substrate 1, and an auxiliary formed on the light shielding film 10. The light-shielding film 20 includes an etching mask film 30 formed on the auxiliary light-shielding film 20, a second etching mask film 40 formed thereon, and a resist film 100.

FIG. 4 shows an example of a mask blank according to the fourth embodiment of the present invention.
In the fourth embodiment, as shown in FIG. 4, a light shielding film 10 having a laminated structure of a light shielding layer 11 and a surface antireflection layer 12 on a light transmitting substrate 1, and etching formed on the light shielding film 10. The auxiliary light-shielding film 20 having a laminated structure of the stopper / mask layer 21 and the auxiliary light-shielding layer 22 formed thereon, the adhesion improving layer 60 formed on the auxiliary light-shielding film 20, and the resist film 100 are provided.

FIG. 5 shows an example of a mask blank according to the fifth embodiment of the present invention.
In the fifth embodiment, as shown in FIG. 5, a light shielding film 10 having a laminated structure of a light shielding layer 11 and a surface antireflection layer 12 on a light transmissive substrate 1, and etching formed on the light shielding film 10. It has an auxiliary light shielding film 20 having a laminated structure of a stopper / mask layer 21 and an auxiliary light shielding layer 22 formed thereon, an etching mask film 70 formed on the auxiliary light shielding film 20, and a resist film 100.

In the present invention, it is preferable that the optical density with respect to exposure light in the laminated layer structure of the light shielding film and the auxiliary light shielding film is 3.1 or more.
The first to fifth embodiments can be applied to binary mask blanks and transfer masks used for single exposure, double patterning, and double exposure.

In the case of a transfer mask used for single exposure or double patterning, the optical density in the light shielding band produced from the light shielding film and the auxiliary light shielding film is 2.8 or more (transmittance is 0.16% or less). It is more preferable that it is 3.0 or more (transmittance is 0.1% or less). For example, when the optical density of the light shielding film 10 is 2.0, the auxiliary light shielding film 20 preferably has an optical density of 0.8 or higher, and more preferably 1.0 or higher.
On the other hand, in the case of a transfer mask used for double exposure, the optical density in the light shielding zone is preferably 3.1 or more (transmittance is 0.08% or less). For example, when the optical density of the light shielding film 10 is 2.0, the optical density of the auxiliary light shielding film 20 is preferably 1.1 or more. In addition, when the optical density required for the light shielding band is more reliably 3.3 or more (transmittance is 0.05% or less), the optical density of the auxiliary light shielding film 20 is preferably 1.3 or more. Further, when the optical density required for the light shielding band is 3.5 or more (transmittance is 0.03% or less), the optical density of the auxiliary light shielding film 20 is preferably 1.5 or more.

In the present invention, since the light shielding film 10 and the auxiliary light shielding film 20 are configured as separate films, a high optical density is required in a region where a light shielding band is to be formed, such as double exposure. However, it can be easily handled without affecting the light shielding film pattern (and thus the EMF characteristics).
Double patterning refers to a patterning method in which a series of steps of resist coating, exposure, development, and resist stripping are performed twice on a wafer. That is, the resist on the wafer is subjected to one transfer pattern exposure as in the case of conventional single exposure, and exposure is performed up to four times in the overlapping exposure portion due to leakage light.

In the present invention, the light shielding layer 11 is preferably made of a material having a very high light shielding property, and is preferably composed of a material having a light shielding property higher than that of chromium.
The light shielding layer 11 is preferably made of a transition metal silicide-based or Ta-based material having a higher optical density than chromium-based. Moreover, it is preferable to use the material developed in order to raise optical density further about these materials.
In the present invention, transition metals are molybdenum (Mo), tantalum (Ta), chromium (Cr), tungsten (W), titanium (Ti), zirconium (Zr), vanadium (V), niobium (Nb), nickel ( It is made of any one of Ni), palladium (Pb), hafnium (Hf), ruthenium (Ru), rhodium (Rh), platinum (Pt) or an alloy.
The light shielding layer 11 is preferably made of a material (high MoSi type) having a light shielding property enhanced to the limit. The light shielding layer 11 can also use a Ta-based material (TaN, TaB, TaBN, etc.).
In the present invention, the light shielding layer 11 can be composed of a transition metal, a transition metal silicide, a compound containing nitrogen, oxygen, carbon, hydrogen, an inert gas (helium, argon, xenon, etc.), or the like. In this case, it is necessary that the film has a film thickness of 40 nm or less and a film satisfying an optical density of 2.0 or more in combination with the surface antireflection layer 12.

In the present invention, the light shielding layer is preferably made of a material containing 90% or more of transition metal silicide.
This is because even if the film thickness of the entire light shielding film 10 including the surface antireflection layer 12 is 40 nm or less, a high light shielding property of an optical density of 2.0 or more is obtained. In order to ensure this light shielding property, the total amount of substances (carbon, hydrogen, oxygen, nitrogen, inert gas (helium, argon, xenon, etc.)) other than transition metal silicide is 10 in the light shielding layer 11. Must be less than%. This is because if it is less than 10%, the light-shielding performance is hardly affected.

For example, when the MoSi-based material is used as the light-shielding layer 11, the light-shielding layer 11 has an optical density of 2.3 to 2.0 at a film thickness of 34 to 30 nm, and when the TaN-based material is used as the light-shielding layer 11, the film thickness 34. The optical density can be 2.3 to 2.0 at ˜30 nm. Further, in the case of a light shielding film having a thickness of 40 nm or less with a laminated structure of the light shielding layer 11 and the surface antireflection layer 12 using MoSi-based material, the thickness of the light shielding layer 11 is 15 nm or more and the optical density is 2.0 or more. Is possible. In the case of a light-shielding film having a thickness of 40 nm or less with a laminated structure of the light-shielding layer 11 and the surface antireflection layer 12 using a Ta-based material, the thickness of the light-shielding layer 11 is 21 nm or more and the optical density is 2.0 or more. Is possible.
At present (when using the most light-shielding material that is currently developed), for example, if the allowable optical density with respect to the effect on the transfer by reducing the optical density is 2.0, the film thickness is reduced. The film thickness of the light-shielding film 10 that can maximize the contribution to improving the problem of the electromagnetic field (EMF) effect is 30 nm.

In the mask blank of the present invention, the surface antireflection layer is preferably made of a material mainly composed of transition metal silicide.
The surface antireflection layer 12 is basically applicable to any material as long as a surface reflectance of a predetermined value or more can be obtained in a laminated structure with the light shielding layer 11, but is made of the same target as the light shielding layer 11. It is preferable to use a material capable of forming a film. When a transition metal silicide-based material is applied to the light shielding layer 11, the surface antireflection layer 12 is made of a material mainly containing transition metal silicide (MSi) (MSiO, MSiN, MSiON, MSiOC, MSiCN, MSiOCN, etc.) Is preferred. In addition, when a Ta-based material is applied to the light shielding layer 11, a material mainly composed of Ta (TaO, TaON, TaBO, TaBON, etc.) is preferable for the surface antireflection layer 12.

In the present invention, the light shielding film 10 or the light shielding layer 11 preferably contains a material containing at least one of carbon (C) and hydrogen (H) in addition to the transition metal (M) and silicon (Si).
The light shielding film 10 containing at least one of carbon (C) and hydrogen (H) in addition to the transition metal (M) and silicon (Si) is not easily oxidized in the film during sputtering film formation. By forming carbide (Si—C bond), transition metal carbide (M—C bond, for example, Mo—C bond), and silicon hydride (Si—H bond), light resistance and the like are excellent. Further, the chemical bond state includes M (transition metal) -Si bond, Si-Si bond, MM bond, MC bond, Si-C bond, and Si-H bond.

In the present invention, as the light shielding film 10 or the light shielding layer 11, a film made of a material containing at least one of carbon (C) and hydrogen (H) in addition to transition metal (M) and silicon (Si) is used. The following effects (1) to (3) can be obtained.
(1) Even when the ArF excimer laser is continuously irradiated so as to have a total irradiation amount of 30 kJ / cm ² (that is, when it is irradiated cumulatively beyond the period of repeated use of the previous mask) Thus, the increase in the line width (CD variation) of the light shielding film pattern can be suppressed to 10 nm or less, preferably 5 nm or less. Thereby, the light resistance can be improved and the life of the transfer mask can be remarkably improved.
(2) Since the etching rate is increased due to the presence of C and / or H (silicon carbide, transition metal carbide, silicon hydride), the resist film is not thickened, and resolution and pattern accuracy deteriorate. Never do. In addition, since the etching time can be shortened, in the case of a structure having an etching mask film on the light shielding film, damage to the etching mask film can be reduced, and high-definition patterning is possible.
(3) Since deposition of transition metal (for example, Mo) caused by cumulative irradiation of ArF excimer laser light can be reduced, deposits on a glass substrate or film due to deposition of transition metal (for example, Mo) should be reduced. Can do. For this reason, the defect by the said deposit can be suppressed.

In the present invention, a thin film comprising a transition metal, silicon, carbon, silicon carbide and / or transition metal carbide is formed by sputtering film formation using a target containing carbon or an atmospheric gas containing carbon. it can.
Here, the hydrocarbon gas is, for example, methane (CH ₄ ), ethane (C ₂ H ₆ ), propane (C ₃ H ₈ ), butane (C ₄ H ₁₀ ), or the like.
By using hydrocarbon gas, carbon and hydrogen (silicon carbide, transition metal carbide, silicon hydride) can be introduced into the film.
By using a target containing carbon, only carbon (silicon carbide, transition metal carbide) can be introduced into the film. In this case, in addition to the embodiment using the MoSiC target, an embodiment using a target containing C in one or both of the Mo target and the Si target, and an embodiment using the MoSi target and the C target are included.

In the present invention, a thin film containing a transition metal, silicon, hydrogen, and containing silicon hydride can be formed by sputtering film formation using an atmospheric gas containing hydrogen.
In this method, only hydrogen (silicon hydride) can be introduced into the film.
This method includes an embodiment using a Mo target and an Si target in addition to an embodiment using a MoSi target. Further, in this method, when carbon (silicon carbide, transition metal carbide) is further included in the film, a target containing C in one or both of the Mo target and the Si target is used in addition to the embodiment using the MoSiC target. A mode to use and a mode to use a MoSi target and a C target are included.

In the present invention, the thin film is preferably formed by adjusting the pressure and / or power of the atmospheric gas during the sputtering film formation.
It is considered that when the pressure of the atmospheric gas is low (in this case, the film formation rate is low), carbides (silicon carbide or transition metal carbide) are easily formed. Further, it is considered that when power is lowered, carbides (silicon carbide and transition metal carbide) are easily formed.
In the present invention, carbide and the like (silicon carbide and transition metal carbide) are formed as described above, and the pressure and / or electric power of the atmospheric gas at the time of the sputtering film formation is obtained so that the above-described effects of the present invention can be obtained. adjust.
Further, the present invention provides a stable Si-C bond and / or a stable transition metal MC bond formed in the film during sputtering film formation so that the above-described effects of the present invention can be obtained. The pressure and / or power of the atmospheric gas during sputtering film formation is adjusted.
On the other hand, it is considered that carbide or the like (silicon carbide or transition metal carbide) is difficult to be formed when the pressure of the atmospheric gas is high (in this case, the film forming speed is high). Moreover, it is thought that it is difficult to form carbides (silicon carbides and transition metal carbides) when the power is lowered.

The carbon content in the light shielding layer 11 is preferably more than 1 atomic% and less than 10 atomic%. When the light shielding layer 11 has a carbon content of 1 atomic% or less, silicon carbide and / or transition metal carbide is difficult to form, and when the carbon content is 10 atomic% or more, the light shielding layer is made thinner. Becomes difficult.
The hydrogen content is preferably more than 1 atomic% and less than 10 atomic%. When the hydrogen content of the light shielding layer is 1 atomic% or less, silicon hydride is hardly formed, and when the hydrogen content is 10 atomic% or more, film formation becomes difficult.

In the present invention, the transition metal silicide in the light shielding layer 11 is molybdenum silicide, and the molybdenum content is preferably 9 atomic% or more and 40 atomic% or less.
This is because it is preferable to use a MoSi-based material having a higher optical density than that of a chromium-based material.

The inventor has shown that the light shielding layer 11 containing molybdenum silicide having a molybdenum content of 9 atomic% or more and 40 atomic% or less has a high optical density per unit film thickness as shown in FIG. The light-shielding layer 11 having a relatively large light-shielding property in light is obtained, and the total film thickness of the light-shielding film 10 is 40 nm or less (when the film thickness of the surface antireflection layer 12 is 5 nm or more, the film thickness of the light-shielding layer 11 is It has been found that a predetermined light-shielding property (optical density of 2.0 or more) can be obtained even with a layer thickness of 35 nm or less.
When the molybdenum content in the light shielding layer 11 containing molybdenum silicide is 9 atomic% or more, ΔOD = 0.075 nm ⁻¹ @ 193.4 nm or more can be achieved. It is more preferable that the molybdenum content is 15 atomic% or more because ΔOD = 0.08 nm ⁻¹ @ 193.4 nm or more. It is more preferable that the molybdenum content is 20 atomic% or more because ΔOD = 0.082 nm ⁻¹ @ 193.4 nm or more.
The content of molybdenum in the light shielding layer 11 containing molybdenum silicide is preferably 15 atomic percent or more and 40 atomic percent or less, and more preferably 19 atomic percent or more and 40 atomic percent or less.
Molybdenum silicide has a problem that when the content of molybdenum is high, chemical resistance and cleaning resistance (particularly alkali cleaning and hot water cleaning) decrease. It is preferable to set it to 40 atomic% or less, which is a molybdenum content that can ensure the minimum necessary chemical resistance and washing resistance when used as a transfer mask. Further, as is clear from FIG. 6, the light shielding performance of molybdenum silicide reaches a predetermined value as the molybdenum content increases. The upper limit of the molybdenum content is preferably up to 40 atomic%, which is a degree to which a stoichiometrically stable ratio of molybdenum silicide is given a certain range, and if molybdenum is included at a higher ratio, chemical resistance and Washing resistance is reduced.
Further, when the Mo content of the light shielding layer 11 is in the range of 9 atomic% or more and 40 atomic% or less, the etching rate in dry etching with a fluorine-based gas is relatively large with respect to the composition outside this range. preferable.

Note that the light-shielding layer containing molybdenum silicide has other elements (carbon, oxygen, nitrogen, inert gas (helium, hydrogen, argon, xenon, etc.) within a range (less than 10%) that does not impair the above characteristics and effects. Etc.).
In the present invention, the light-shielding layer 11 made of molybdenum silicide preferably has a lower layer thickness of 24 nm or more, more preferably 27 nm or more, and an upper layer thickness of less than 40 nm. Desirably, it is more desirable that it is less than 35 nm. In the case of a structure in which an optical density of 2.0 or more is ensured by a laminated structure of the light shielding layer 11 made of molybdenum silicide and the surface antireflection layer 12, the lower limit of the thickness of the light shielding layer 11 is 15 nm. Is possible.

  In the present invention, the MoSi light shielding layer 11 can freely control the tensile stress and the compressive stress by the gas pressure and heat treatment in the sputtering chamber. For example, by controlling the film stress of the MoSi light-shielding layer 11 to be a tensile stress, it is possible to match the compressive stress of the surface antireflection layer 12 (for example, MoSiON). That is, the stress of each layer constituting the light shielding film 10 can be offset, and the film stress of the light shielding film 10 can be reduced as much as possible (can be substantially zero).

  In the present invention, examples of the surface antireflection layer 12 made of a molybdenum silicide compound containing at least one of oxygen and nitrogen include MoSiON, MoSiO, MoSiN, MoSiOC, and MoSiOCN. Among these, MoSiO and MoSiON are preferable from the viewpoint of chemical resistance and heat resistance, and MoSiON is preferable from the viewpoint of blanks defect quality. Further, when Mo is increased, the washing resistance, particularly the resistance to alkali (ammonia water or the like) or warm water is reduced. From this viewpoint, it is preferable to reduce the content of Mo in the surface antireflection layer 12 as much as possible.

  Further, it was found that when heat treatment (annealing) is performed at a high temperature for the purpose of stress control, a phenomenon that the surface of the film becomes cloudy white (clouds) occurs when the Mo content is large. This is considered to be because MoO precipitates on the surface. From the viewpoint of avoiding such a phenomenon, the Mo content in the surface antireflection layer 12 is preferably less than 10 at%. However, when the Mo content is too small, abnormal discharge during DC sputtering becomes significant, and the frequency of occurrence of defects increases. Therefore, it is desirable that Mo is contained within a range where it can be sputtered normally. Depending on other film formation techniques, film formation may be possible without containing Mo.

In the present invention, the light shielding film 10 is preferably made of a Ta-based material.
In order to ensure that the total film thickness of the light shielding film 10 is 40 nm or less, which is a film thickness that is less affected by the electromagnetic field (EMF) effect, and to ensure an optical density of 2.0 or higher, the optical density is higher than that of a chromium-based film. This is because it is preferable to use a Ta-based material.
In the Ta-based light shielding film 10, the light shielding layer 11 and the surface antireflection layer 12 can have a laminated structure of tantalum or a compound thereof. Examples of tantalum compounds include tantalum nitrides, oxides, borides, carbides, and the like.

In the present invention, the light shielding film 10 includes two layers, a light shielding layer 11 made of tantalum nitride, and a surface antireflection layer 12 made of tantalum oxide, which is formed on and in contact with the light shielding layer 11. ,
The aspect which consists of consists of.
By nitriding the tantalum of the light shielding layer 11, it is possible to prevent oxidation of the transfer pattern side wall of the light shielding film 10 after the transfer mask is produced. On the other hand, in order to ensure high light-shielding performance, it is desirable to reduce the nitrogen content as much as possible. Considering these points, the nitrogen content in the light-shielding layer is preferably 1 atom% or more and 20 atom% or less, and more preferably 5 atom% or more and 10 atom% or less.
The surface antireflection layer 12 made of a tantalum oxide containing 50 atomic% or more of oxygen is preferable because of its excellent antireflection effect.
With the configuration as described above, reflection prevention on the surface side of the light shielding film 10 is achieved. Thus, it is effective to improve the problem of the electromagnetic field (EMF) effect to make the film thinner by a structure in which the back surface antireflection layer is omitted.

In the present invention, the light shielding film 10 has a laminated structure of the light shielding layer 11 and the surface antireflection layer 12, the total film thickness is 40 nm or less, the optical density with respect to ArF exposure light is at least 2.0, and the surface reflectance. Is preferably a predetermined value (for example, 30% or less).
When designing such a light-shielding film 10, a film structure that mostly depends on the light-shielding layer 11 for contribution to the optical density is often used, but a film structure that contributes to the optical density to the surface antireflection layer 12 is also possible. In this case, the appropriate ranges of the refractive index n and the extinction coefficient k of the light shielding layer 11 and the surface antireflection layer 12 are different from the conventional film configuration that relies on the light shielding layer 11 for the contribution to the optical density. The following refractive index n and extinction coefficient k are numerical values for ArF exposure light (wavelength 193 nm), and so on.

In the case where the surface antireflection layer 12 also has a film structure that contributes somewhat to the optical density, the extinction coefficient k of the light shielding layer 11 can be lowered. For example, the extinction coefficient k of the light shielding layer 11 may be 1.8 or more, preferably 1.9 or more, and more desirably 2.0 or more. The extinction coefficient k of the light shielding layer 11 is preferably 2.4 or less, preferably 2.3 or less, and more preferably 2.2 or less.
On the other hand, the refractive index n of the light shielding layer 11 in this case is desirably low. For example, the refractive index n of the light shielding layer 11 may be 1.5 or more, preferably 1.6 or more, and more preferably 1.7 or more. Moreover, the extinction coefficient k of the light shielding layer 11 is good in it being 2.4 or less, Preferably it is 2.0 or less, More preferably, it is 1.8 or less.

In the case where the surface antireflection layer 12 also has a film structure that contributes somewhat to the optical density, the extinction coefficient k of the surface antireflection layer 12 is increased. For example, the extinction coefficient k of the surface antireflection layer 12 is preferably 0.7 or more, preferably 0.8 or more, and more desirably 0.9 or more. The extinction coefficient k of the surface antireflection layer 12 is preferably 1.5 or less, preferably 1.4 or less, more preferably 1.3 or less.
On the other hand, the refractive index n of the surface antireflection layer 12 in this case is desirably slightly lower than usual for low reflection. For example, the refractive index n of the surface antireflection layer 12 may be 1.7 or more, preferably 1.8 or more, and more desirably 1.9 or more. The refractive index n of the surface antireflection layer 12 is preferably 2.4 or less, preferably 2.2 or less, more preferably 2.0 or less.

In the present invention, it is preferable that the auxiliary light shielding film has resistance to an etching gas used when the light shielding film is etched.
For example, in the embodiment in which the auxiliary light shielding film 20 is formed in contact with the light shielding film 10 as in the first to third embodiments of FIGS. This is because a transfer mask having a light shielding band formed on the outer periphery of the pattern region can be manufactured. This is also because the light shielding film 10 can be etched using the auxiliary light shielding film 20 as an etching mask.

In one aspect of the present invention, the auxiliary light-shielding film 20 is preferably formed of a material mainly containing any one of chromium, chromium nitride, chromium oxide, chromium nitride oxide, and chromium oxycarbonitride.
Most materials (metal silicide type, Ta type) that can be applied to the light shielding film 10 can be dry-etched with a fluorine-based gas. For this reason, it is preferable to use a material having resistance to the fluorine-based gas for the auxiliary light shielding film 20. Since the chromium-based material is highly resistant to fluorine-based gas and is basically a material that can be dry-etched with a mixed gas of chlorine and oxygen, it is formed in the upper layer of the auxiliary light shielding film 20 (for example, the resist film 100). When performing dry etching to transfer the transfer pattern to the auxiliary light shielding film 20, the lower light shielding film 10 can function as an etching stopper. As a result, the transfer pattern can be transferred by dry-etching the lower light shielding film 10 using the auxiliary light shielding film 20 as an etching mask, and the transfer pattern can be formed on the light shielding film 10 with high accuracy.
In the present invention, as the auxiliary light shielding film 20, for example, a material such as chromium alone or a material containing at least one element composed of oxygen, nitrogen, carbon, and hydrogen in chromium (a material containing Cr) is used. it can. As the film structure of the auxiliary light shielding film 20, a single layer or a multiple layer structure made of the above film material can be used. The multi-layer structure can be a multi-layer structure formed stepwise with different compositions, or a film structure in which the composition is continuously changed.

In one embodiment of the present invention, the auxiliary light-shielding film contains at least one of nitrogen and oxygen in chromium, the chromium content in the film is 50 atomic% or less, and the film thickness is 20 nm. The above is preferable.
For example, in the first to third embodiments shown in FIGS. 1 to 3, for example, when the light shielding film is made of a MoSi-based material, the chromium contains at least one component of nitrogen and oxygen, When the chromium content in the film is 50 atomic% or less, preferably 45 atomic% or less, the etching rate of the auxiliary light shielding film 20 can be increased to reduce the resist film thickness, and the film thickness can be reduced. By setting the thickness to 20 nm or more, an optical density of 0.8 or more required for the auxiliary light shielding film 20 can be secured.
In the present invention, the auxiliary light shielding film 20 made of a chromium-based material preferably has a thickness of 20 nm to 40 nm.

In the present invention, it is preferable that an etching mask film having resistance to an etching gas used when etching the auxiliary light shielding film is provided on the auxiliary light shielding film.
For example, in the second and third embodiments shown in FIGS. 2 and 3, when the auxiliary light shielding film 20 is formed of the chromium-based material, the etching mask film 30 is a mixture of chlorine and oxygen. It is preferable to select a material having resistance to dry etching with gas. For example, silicon oxide, nitride, or oxynitride, or a material in which a transition metal is contained in these materials at a low ratio (8% or less) can be used. As the transition metal, those applied in the light shielding layer 11 are preferable.

  Further, as in the second embodiment shown in FIG. 2, an adhesion improving layer 60 that improves the adhesion between the resist film 100 and the etching mask film 30 may be formed. As the adhesion improving layer 60, for example, a configuration in which an HMDS (hexamethyldisilazane) layer is formed on the surface of the etching mask film 30 by transpiration is first mentioned. In addition, the resist is not dissolved in a developer used when forming a resist pattern on the resist film 100, and is etched together when the etching mask film 30 is dry-etched using the resist pattern as a mask. A structure in which a resin layer having a characteristic of being removed at the time of removal treatment (solvent removal, oxygen plasma ashing, etc.) is also included.

  Further, as in the third embodiment shown in FIG. 3, the second etching mask film 40 may be formed on the etching mask film 30 (corresponding to the etching mask film 30 in FIG. 2). In the case where the etching mask film 30 is formed of the silicon-based material or the transition metal-based material, the chromium-based material is preferable for the second etching mask film 40.

In the present invention, the auxiliary light shielding film is provided between the auxiliary light shielding layer, the light shielding film and the auxiliary light shielding layer, and an etching gas used for etching the auxiliary light shielding layer, and when the light shielding film is etched. And an etching stopper / mask layer having resistance to any of the etching gases used in the process.
In one embodiment of the present invention, the etching stopper / mask layer includes at least one of nitrogen and oxygen in chromium, and the chromium content in the film is 50 atomic% or less, and The film thickness is preferably 5 nm or more and 20 nm or less.
Furthermore, in one embodiment of the present invention, it is preferable that the auxiliary light shielding layer is made of a material containing transition metal silicide as a main component.

For example, when the transfer pattern is formed by etching the light shielding film 10 by providing the etching stopper / mask layer 21 on the light shielding film 10 side of the auxiliary light shielding film 20 as in the fourth embodiment of FIG. Since the etching mask can be used as the etching stopper / mask layer 21, the etching mask can be made thinner as compared with the case where the auxiliary light shielding film 20 with optical density restriction is used as the etching mask. Therefore, a transfer pattern can be formed with high accuracy.
For the auxiliary light shielding layer 22, a material to be etched with an etching gas when the light shielding film 10 is etched can be selected. The same material as that applied to the light shielding film 10 can be applied to the auxiliary light shielding layer 22.

In the present invention, a metal film containing metal can be used as the auxiliary light shielding layer 22.
As a metal film containing a metal, tantalum, molybdenum, titanium, hafnium, tungsten, an alloy containing these elements, or a material containing the above elements or the above alloys (for example, oxygen in addition to the above elements or a material containing the above alloys) , A film including at least one of nitrogen, silicon, and carbon), and may have a multi-layer structure formed stepwise with different compositions or a multi-layer structure where the composition is continuously changed.

In the present invention, the auxiliary light shielding layer 22 may be composed of a silicide of the transition metal, a compound containing nitrogen, oxygen, carbon, hydrogen, an inert gas (such as helium, argon, xenon) or the like. .
In the present invention, the metal film is a film made of one or two or more materials selected from aluminum, titanium, vanadium, chromium, zirconium, niobium, molybdenum, lanthanum, tantalum, tungsten, silicon, and hafnium, or nitriding these Products, oxides, oxynitrides, carbides, and the like.

The auxiliary light shielding layer 22 is preferably made of a MoSi material.
For example, when the light shielding film 10 is made of a MoSi material, the etching stopper / mask layer 21 is preferably made of a chromium material, and the auxiliary light shielding layer 22 is preferably made of a MoSi material. In addition, since the MoSi-based material can select a film having a high light shielding property, the auxiliary light shielding layer 22 can be made thinner.
In the present invention, the thickness of the auxiliary light shielding layer 22 made of a MoSi-based material is preferably 10 nm to 30 nm when the molybdenum content in the auxiliary light shielding layer 22 is 20 atomic%.
Further, as in the second embodiment, the adhesion improving layer 60 made of the HMDS layer, the resin layer, or the like for improving the adhesion between the resist film 100 and the auxiliary light shielding layer 22 is formed.

In the present invention, the etching mask films such as the second etching mask film 40, the etching mask film 70, and the etching stopper / mask layer 21 may be made of a chromium-based material.
Such an etching mask film can be made thin by forming it with a chromium-based material. Moreover, it is excellent in processing accuracy. Furthermore, the etching selectivity with respect to the layer formed in contact with the upper and lower sides of the etching mask film is high, and the unnecessary etching mask film can be removed without damaging other layers.
In the present invention, for the etching mask film, for example, a material such as chromium alone or a material containing at least one element composed of oxygen, nitrogen, carbon, and hydrogen in chromium (a material containing Cr) can be used. . The film structure of the etching mask film is often a single layer made of the above film material, but may be a multi-layer structure. In addition, the multi-layer structure can be a multi-layer structure formed in stages with different compositions or a film structure in which the composition is continuously changed.
In the present invention, the etching mask film preferably has a thickness of 5 nm to 20 nm. According to such a configuration, the shift amount of the CD of the etching target film with respect to the CD (Critical Dimension) of the etching mask film (the dimensional change amount of the pattern dimension of the etching target film with respect to the pattern dimension of the etching mask layer) is less than 5 nm. A certain transfer mask can be obtained.

  In the present invention, the etching mask film contains at least one of nitrogen and oxygen in chromium, the chromium content in the film is 50 atomic% or less, and the film thickness is 5 nm or more and 20 nm. The following is preferable.

When performing processing using a mask blank provided with a MoSi light-shielding film, a Cr-based etching mask film, and a resist film (thickness of 100 nm or less) in this order (in contact with each other) on a translucent substrate In addition,
(1) The thickness of the resist film may not be reduced by simply reducing the thickness of the etching mask film (for example, 20 nm or less).
(2) From the viewpoint of reducing the film thickness of the resist film, the Cr-based etching mask film is not preferable for a material rich in Cr component because the etching rate of chlorine-based (Cl ₂ + O ₂ ) dry etching is slow. From the viewpoint, the Cr-based etching mask film is preferably a highly nitrided and highly oxidized Cr-based material with a small Cr component.
(3) From the viewpoint of reducing LER (Line Edge Roughness) of the light-shielding film pattern, a Cr-based etching mask film is preferably a material rich in Cr component because it has higher resistance to fluorine-based dry etching. The Cr-based etching mask film is preferably a Cr-based material with a large amount of Cr component.
(4) The above (2) and (3) are in a trade-off relationship, and considering this, the Cr-based etching mask film has a chromium content of 50 atomic% or less, and further 45 atomic%. Preferably, the chromium content in the Cr-based etching mask film is preferably 35 atomic% or less, and the lower limit of the chromium content in the Cr-based etching mask film is 20 atoms. % Or more is preferable, more preferably 30 atomic% or more is preferable. Particularly, when the etching mask film is a chromium oxide film, 33 atomic% or more is preferable.
(5) Related to the above (2) and (4) (that is, related to shortening the etching time of the Cr-based etching mask film), and from the viewpoint of reducing the film thickness of the resist film, the film of the Cr-based etching mask film The thickness is preferably 20 nm or less,
(6) Related to the above (3) and (4) (that is, related to the etching resistance of the Cr-based etching mask film), the etching mask is masked until the etching process for transferring the mask pattern to the lower light shielding film is completed. Since the pattern must be able to be maintained, the thickness of the Cr-based etching mask film is preferably 5 nm or more,
I found out.

In the present invention, the etching mask film is formed of a material mainly containing any one of chromium oxycarbonitride (CrOCN), chromium oxide carbide (CrOC), chromium oxynitride (CrON), and chromium nitride (CrN). It is preferable that
The etching rate with respect to chlorine-type gas improves, so that Cr-type material advances oxidation. Further, although not as much as when oxidized, the etching rate with respect to the chlorine-based gas is improved even if nitriding is advanced. Therefore, it is preferable to not only make the chromium content of the etching mask film 35 atomic% or less but also highly oxidize and highly nitride.
From the viewpoint of excellent defect quality of the film, chromium oxycarbonitride and chrome oxide are preferable. Further, from the viewpoint of stress controllability (a low stress film can be formed), chromium oxycarbonitride (CrOCN) is preferable.
The film structure of the etching mask film is often a single layer made of the above film material, but may be a multi-layer structure. In addition, the multi-layer structure can be a multi-layer structure formed in stages with different compositions or a film structure in which the composition is continuously changed.

In the present invention, the etching mask film is made of chromium oxycarbonitride or chromium oxycarbide and uses a chromium target, and at least “CO ₂ gas, N ₂ gas and rare gas” or “CO ₂ gas”. And a rare gas ”(select a gas system with low hysteresis), and the film is formed under conditions near the start of the transition from the metal mode to the reaction mode, or near the reaction mode. preferable.
This is because a film having a high etching rate can be stably produced in DC sputtering.
Specifically, as shown in FIG. 7, in DC sputtering, when plasma is formed, the relationship between the voltage [V] on the vertical axis (corresponding to the film formation rate) and the flow rate of each gas shown on the horizontal axis. Check out.
The case where the flow rate of each gas shown on the horizontal axis is increased from 0 to 50 sccm (bound route) and the case where it is decreased from 50 to 0 sccm (return route) do not coincide with each other, and so-called hysteresis is shown.

The metal mode is a region maintaining a high voltage (for example, 330 to 350 V) (a region where Cr is ion-sputtered by Ar), the transition region is a region where the voltage suddenly drops, and the reaction mode is a region after the sudden drop of the suddenly dropped voltage ( (Region where the voltage 290 to 310 V, which has dropped rapidly) is maintained (region where gas is activated and shows reactivity).
The metal mode is a region of 0 to 30 sccm in FIG. 7 (1), a region of 0 to 25 sccm in FIG. 7 (2), and a region of 0 to 32 sccm in FIG. 7 (3).
The transition region is a region of 35-50 sccm in the increase mode in FIG. 7 (1), a region of 35-50 sccm in the increase mode in FIG. 7 (2), and a region of 43-50 sccm in the increase mode in FIG. 7 (3). .
The reaction region is a region of 50 to 35 sccm in the decrease mode in FIG. 7 (1), a region of 50 to 35 sccm in the decrease mode in FIG. 7 (2), and a region of 48 to 32 sccm in the decrease mode in FIG. .

In the metal mode, a chromium film having a very low degree of oxidation and nitridation is formed. In the reaction mode, a chromium film having a high degree of oxidation and nitridation is formed. In the transition region), the conditions are not stable and are not normally used.
Although there are various gas systems for oxidizing and nitriding chromium, as shown in FIG. 7 (3), when a gas system with large hysteresis (NO gas + noble gas) is used, chromium oxidized and nitrided by DC sputtering is used. It is difficult to stably form a film with low defects in the reaction mode. The same applies when O ₂ gas + rare gas is used.

On the other hand, as shown in FIG. 7 (1) and FIG. 7 (2), when a gas system with small hysteresis is used (in FIG. 7 (1), “CO ₂ gas + rare gas” is used, and FIG. 2) “CO ₂ gas + N ₂ gas + rare gas” is used, and chromium which is oxidized and nitrided by DC sputtering is used in a reaction mode (in FIG. 7A, a reduction mode region of 40 to 30 sccm, FIG. ) In a reduced mode region of 35 to 25 sccm) can be stably formed with low defects, and the obtained oxidized and nitrided chromium can produce a film with a high etching rate. In particular, in FIG. 7 (1) and FIG. 7 (2), where the increase mode and the decrease mode near 35 sccm are slightly deviated (conditions), that is, conditions for going from metal mode to reaction mode (from metal mode to reaction mode). By forming the film in the vicinity (immediately before the transition to), an oxidized and nitrided chromium film having a relatively high etching rate compared to other conditions can be stably produced by DC sputtering with low defects. it can.

The transfer mask of the present invention is produced using the mask blank described above.
That is, the transfer mask of the present invention is a transfer mask to which ArF exposure light is applied, and has a laminated structure of a light-shielding layer and a surface antireflection layer formed on a translucent substrate, and is formed in a transfer pattern region. A light-shielding film pattern having a transfer pattern, and an auxiliary light-shielding film pattern having a light-shielding band pattern formed above the light-shielding film pattern in the outer peripheral region of the transfer pattern region, the light-shielding film pattern having a thickness of 40 nm or less, In addition, an optical density with respect to the exposure light is 2.0 or more and 2.7 or less, and a light-shielding band having an optical density with respect to the exposure light of 2.8 or more is formed by the laminated structure of the light-shielding film pattern and the auxiliary light-shielding film pattern. A configuration is preferred.
Furthermore, the light shielding layer in the light shielding film pattern preferably has a film thickness of 15 nm or more and 35 nm or less.

  Here, the transfer pattern region refers to a region on the main surface where the transfer pattern is disposed on the light shielding film (formed by etching). A transfer pattern (mask pattern) relating to a semiconductor device is usually arranged in a 132 mm × 104 mm region, and when a transfer pattern is exposed and drawn on a resist film on a mask blank, a light shielding film or a translucent substrate is used. Depending on the defect position, the arrangement may be rotated 90 degrees. For this reason, the transfer pattern region is desirably a region within a 132 mm square with respect to the center of the substrate. The light shielding band is intended to shield the leakage light of the exposure light applied to the transfer pattern area, and is preferably formed in the outer peripheral area of the transfer pattern area.

As a result, it has a sufficient improvement effect on the problem of the electromagnetic field (EMF) effect which is a problem in the generation of DRAM half pitch (hp) 32 nm or later, which is a design specification of a semiconductor device, and has a practical use for transfer. A mask can be provided.
The transfer mask of the present invention can be applied to a transfer mask used for single exposure, double patterning, and double exposure.

In the present invention, it is preferable to use a dry etching gas comprising a mixed gas containing a chlorine-based gas and an oxygen gas for the dry etching of the chromium-based thin film. The reason for this is that for a chromium-based thin film made of a material containing chromium and an element such as oxygen and nitrogen, the dry etching rate can be increased by performing dry etching using the above dry etching gas, This is because the dry etching time can be shortened and a thin film pattern having a good cross-sectional shape can be formed. Examples of the chlorine-based gas used for the dry etching gas include Cl ₂ , SiCl ₄ , HCl, CCl ₄ , CHCl _{3, and the} like.

In the present invention, the dry etching of the metal silicide thin film includes, for example, fluorine-based gases such as SF ₆ , CF ₄ , C ₂ F ₆ , CHF ₃ , and these, and He, H ₂ , N ₂ , Ar, C _2. H _{4, O 2} mixed gas, etc., or _{Cl 2, CH} 2 _Cl 2 or the like chlorine-based gas or these with _{He, H 2, N 2,} Ar, be a mixed gas such as C 2 _{H 4} it can.

In the present invention, the resist for forming the resist film 100 is preferably a chemically amplified resist. This is because it is suitable for high-precision processing.
The present invention is applied to generations of mask blanks with a resist film thickness of 100 nm or less, a resist film thickness of 75 nm or less, and a resist film thickness of 50 nm.
In the present invention, the resist is preferably an electron beam drawing resist. This is because it is suitable for high-precision processing.
The present invention is applied to a mask blank for electron beam drawing in which a resist pattern is formed by electron beam drawing.

In the present invention, the translucent substrate 1 includes a synthetic quartz substrate, a CaF ₂ substrate, a soda lime glass substrate, a non-alkali glass substrate, a low thermal expansion glass substrate, an aluminosilicate glass substrate, and the like.

In the present invention, the mask blank includes a mask blank and a mask blank with a resist film.
In the present invention, the transfer mask includes a binary mask and a reticle that do not use the phase shift effect.

Hereinafter, the present invention will be described more specifically with reference to examples.
Example (1-1)
(Manufacture of mask blank)
FIG. 1 is a cross-sectional view of the binary mask blank of Example (1-1).
A synthetic quartz glass substrate having a size of 6 inches square and a thickness of 0.25 inches is used as the light-transmitting substrate 1. Each of the antireflection layers 12) was formed.
Specifically, using a DC magnetron sputtering apparatus, using a target of Mo: Si = 21 atomic%: 79 atomic%, a mixed gas atmosphere of Ar, CH ₄ and He (gas flow ratio Ar: CH ₄ : He) = 10: 1: 50), gas pressure: 0.3 Pa, DC power supply power: 2.0 kW, a film made of molybdenum, silicon, carbon and hydrogen (Mo: 19.8 atomic%, Si: 76.). 7 at%, C: 2.0 at%, H: 1.5 at%) were formed with a film thickness of 15 nm to form a MoSiCH film (light shielding layer 11).
Next, using a target of Mo: Si = 4 atomic%: 96 atomic%, Ar, O ₂ , N ₂ and He (gas flow ratio Ar: O ₂ : N ₂ : He = 6: 5: 11: 16), A film made of molybdenum, silicon, oxygen, and nitrogen (Mo: 2.6 atomic%, Si: 57.1 atomic%, O: 15.5) under conditions of gas pressure: 0.1 Pa and DC power supply: 3.0 kW. 9 atom%, N: 24.4 atom%) was formed with a film thickness of 15 nm to form a MoSiON film (surface antireflection layer 12).
The total film thickness of the light shielding film 10 was 30 nm. The optical density (OD) of the light-shielding film 10 was 2.0 at a wavelength of 193 nm of ArF excimer laser exposure light.
Next, the substrate was heated (annealed) at 450 ° C. for 30 minutes.

Next, the auxiliary light shielding film 20 was formed on the light shielding film 10 (FIG. 8 (1)).
Specifically, using a DC magnetron sputtering apparatus, using a chromium target, a mixed gas atmosphere of Ar, CO ₂ , N ₂ and He (gas flow ratio Ar: CO ₂ : N ₂ : He = 21: 37: 11:31), gas pressure: 0.2 Pa, DC power supply power: 1.8 kW, voltage: 334 V, near (starting) the transition from the metal mode to the reaction mode (near the CO ₂ flow rate of 37 sccm) Film formation was performed (see FIG. 7B), and a CrOCN film (Cr content in the film: 33 atomic%) was formed to a thickness of 30 nm. At this time, by annealing the CrOCN film at a temperature lower than the annealing temperature of the light shielding film 10, the stress of the CrOCN film is made as low as possible without affecting the film stress of the light shielding film 10 (preferably, the film stress is substantially zero). It adjusted so that it might become.
As described above, a mask blank in which the auxiliary light shielding film 20 and the light shielding film 10 for ArF excimer laser exposure and single exposure were formed was obtained.
For elemental analysis of the thin film, Rutherford backscattering analysis was used. The same applies to the following examples and comparative examples.

In the binary mask blank of this example (1-1) shown in FIG. 1, the light shielding film 10 includes a light shielding layer 11 made of MoSiCH whose Mo content in the film is 19.8 atomic%, and Mo content in the film. It was set as the laminated structure of the surface antireflection layer 12 which consists of MoSiON whose quantity is 2.6 atomic%. The light shielding film 10 has a thickness of 30 nm and an optical density of 2.0.
The auxiliary light shielding film 20 is made of CrOCN having a Cr content of 33 atomic% in the film, and has an optical density of 0.8 with a film thickness of 30 nm.

(Preparation of transfer mask)
On the auxiliary light shielding film 20 of the mask blank, a chemically amplified positive resist 100 (PRL009: manufactured by Fuji Film Electronics Materials) for electron beam drawing (exposure) was applied by spin coating so as to have a film thickness of 100 nm. (FIG. 1, FIG. 8 (1)).
Next, a desired pattern was drawn on the resist film 100 using an electron beam drawing apparatus, and then developed with a predetermined developer to form a resist pattern 100a (FIG. 8 (2)).
Next, the auxiliary light shielding film 20 was dry-etched using the resist pattern 100a as a mask to form the auxiliary light shielding film pattern 20a (FIG. 8 (3)). As a dry etching gas, a mixed gas of Cl ₂ and O ₂ (Cl ₂ : O ₂ = 4: 1) was used.
Next, the remaining resist pattern 100a was peeled off with a chemical solution.
Next, using the auxiliary light shielding film pattern 20a as a mask, the light shielding film 10 was dry-etched using a mixed gas of SF ₆ and He to form the light shielding film pattern 10a (FIG. 8 (4)).
Next, the resist pattern 100a is peeled off, and a resist film 110 of an electron beam drawing (exposure) positive resist (FEP171: manufactured by Fuji Film Electronics Materials Co., Ltd.) is formed on the substrate by a spin coating method to a film thickness of 200 nm. ] (FIG. 8 (5)).
Next, the resist film 110 is subjected to drawing exposure with a pattern of a light shielding portion (light shielding band) using an electron beam lithography apparatus and developed with a predetermined developer to form a resist pattern 110b (FIG. 8 (6)). ) Using this resist pattern 110b as a mask, the auxiliary light shielding film pattern 20a was etched by dry etching with a mixed gas of Cl ₂ and O ₂ (Cl ₂ : O ₂ = 4: 1) to form the auxiliary light shielding film pattern 20b. (FIG. 8 (7)).
Next, the resist pattern 110b is peeled off, subjected to predetermined cleaning, and for binary transfer having a light-shielding portion (light-shielding band) 80 composed of the auxiliary light-shielding film pattern 20b and the portion of the light-shielding film pattern 10a therebelow. A mask was obtained (FIG. 8 (8)).

  With regard to the binary transfer mask of this example (1-1), with ArF exposure light, the problem of the electromagnetic field (EMF) effect which becomes a problem in the generation after DRAM half pitch (hp) 32 nm in the design specification of the semiconductor device. On the other hand, it was confirmed that a transfer mask having a sufficient improvement effect and practicality can be provided.

  In the transfer mask manufacturing example, the resist pattern 100a is peeled and removed after the auxiliary light shielding film pattern 20a is formed. However, the resist pattern 100a can be peeled and removed after the light shielding film pattern 10a is formed.

Example (1-2)
(Manufacture of mask blank)
Example (1-2) is the same as Example (1-1) except that the light shielding layer 11 was prepared under the following conditions, and the Mo content in the MoSiCH film was 32.3 atomic%. The same as (1-1).
In Example (1-2), a target of Mo: Si = 1: 2 was used, and a mixed gas atmosphere of Ar, CH ₄ and He (gas flow ratio Ar: CH ₄ : He = 10: 1: 50) was used. A film made of molybdenum, silicon, carbon and hydrogen (Mo: 32.3 atomic%, Si: 64.6 atomic%, C: 1. 8 atomic%, H: 1.3 atomic%) was formed with a film thickness of 15 nm to form a MoSiCH film (light shielding layer 11).

In the binary mask blank of this example (1-2) shown in FIG. 1, the light shielding film 10 includes a light shielding layer 11 made of MoSiCH whose Mo content in the film is 32.3 atomic%, and Mo content in the film. It was set as the laminated structure of the surface antireflection layer 12 which consists of MoSiON whose quantity is 2.6 atomic%. The light shielding film 10 has a thickness of 30 nm and an optical density of 2.0.
The auxiliary light shielding film 20 is made of CrOCN having a Cr content of 33 atomic% in the film, and has an optical density of 0.8 with a film thickness of 30 nm.

(Preparation of transfer mask)
Using the binary mask blank of this example (1-2), a binary transfer mask of this example (1-2) was produced in the same manner as in the above example (1-1).
About the binary transfer mask of this example (1-2), with ArF exposure light, the problem of the electromagnetic field (EMF) effect which becomes a problem in the generation after DRAM half pitch (hp) 32 nm in the design specification of the semiconductor device. On the other hand, it was confirmed that a transfer mask having a sufficient improvement effect and practicality can be provided.

Example (1-3)
(Manufacture of mask blank)
FIG. 1 is a cross-sectional view of the binary mask blank of this example (1-3).
A synthetic quartz glass substrate having a size of 6 inches square and a thickness of 0.25 inches is used as the light-transmitting substrate 1, and a tantalum nitride (TaN) film (light-blocking layer 11) is formed on the light-transmitting substrate 1 as the light-blocking film 10. A tantalum oxide (TaO) film (surface antireflection layer 12) was formed.
Specifically, a DC magnetron sputtering apparatus is used, a Ta target is used, the introduced gas and its flow rate: Ar = 39.5 sccm, N ₂ = 3 sccm, the power of the DC power source: 1.5 kW, and the film thickness is 26 nm. A film made of tantalum nitride (TaN) (Ta: 93 atomic%, N: 7 atomic%) was formed. Next, using the same Ta target, the introduced gas and its flow rate: Ar = 58 sccm, O ₂ = 32.5 sccm, DC power supply power: 0.7 kW, and made of tantalum oxide (TaO) with a film thickness of 10 nm. A film (Ta: 42 atomic%, O: 58 atomic%) was formed.
The total film thickness of the light shielding film 10 was 36 nm. The optical density (OD) of the light-shielding film 10 was 2.0 at a wavelength of 193 nm of ArF excimer laser exposure light.

Next, the auxiliary light shielding film 20 was formed on the light shielding film 10 (FIG. 1).
Specifically, using a DC magnetron sputtering apparatus, using a chromium target, a mixed gas atmosphere of Ar, CO ₂ , N ₂ and He (gas flow ratio Ar: CO ₂ : N ₂ : He = 21: 37: 11:31), gas pressure: 0.2 Pa, DC power supply power: 1.8 kW, voltage: 334 V, near (starting) the transition from the metal mode to the reaction mode (near the CO ₂ flow rate of 37 sccm) A film was formed (see FIG. 7B), a CrOCN film (Cr content in the film: 33 atomic%) was formed to a thickness of 30 nm, and the auxiliary light shielding film 20 was formed.
As described above, a mask blank in which the auxiliary light shielding film 20 and the light shielding film 10 for ArF excimer laser exposure and single exposure were formed was obtained.
For elemental analysis of the thin film, Rutherford backscattering analysis was used.

In the binary mask blank of this embodiment (1-3) shown in FIG. 1, the light shielding film 10 includes a light shielding layer 11 made of TaN having an N content of 7 atomic% in the film, and 58 atoms of O in the film. %, A laminated structure of the surface antireflection layer 12 made of TaO. The light shielding film 10 has a thickness of 36 nm and an optical density of 2.0.
The auxiliary light shielding film 20 is made of CrOCN having a Cr content of 33 atomic% in the film, and has an optical density of 0.8 with a film thickness of 30 nm.

(Preparation of transfer mask)
On the auxiliary light shielding film 20 of the mask blank, a chemically amplified positive resist 100 (PRL009: manufactured by Fuji Film Electronics Materials) for electron beam drawing (exposure) was applied by spin coating so as to have a film thickness of 100 nm. (FIG. 1, FIG. 8 (1)).
Next, a desired pattern was drawn on the resist film 100 using an electron beam drawing apparatus, and then developed with a predetermined developer to form a resist pattern 100a (FIG. 8 (2)).
Next, the auxiliary light shielding film 20 is dry-etched using the resist pattern 100a as a mask to form the auxiliary light shielding film pattern 20a (FIG. 8 (3)). As a dry etching gas, a mixed gas of Cl ₂ and O ₂ (Cl ₂ : O ₂ = 4: 1) was used.
Next, the remaining resist pattern 100a was peeled off with a chemical solution.
Next, using the auxiliary light shielding film pattern 20a as a mask, the light shielding film 10 was dry etched to form the light shielding film pattern 10a (FIG. 8D). At this time, a mixed gas of CHF ₃ and He was used as a dry etching gas for the tantalum oxide (TaO) layer 12. As a dry etching gas for the tantalum nitride (TaN) layer 11, Cl ₂ gas was used.
Next, the resist pattern 100a is peeled off, and a resist film 110 of an electron beam drawing (exposure) positive resist (FEP171: manufactured by Fuji Film Electronics Materials Co., Ltd.) is formed on the substrate by a spin coating method to a film thickness of 200 nm. ] (FIG. 8 (5)).
Next, the resist film 110 is subjected to drawing exposure with a pattern of a light shielding portion (light shielding band) using an electron beam lithography apparatus and developed with a predetermined developer to form a resist pattern 110b (FIG. 8 (6)). ) Using this resist pattern 110b as a mask, the auxiliary light shielding film pattern 20a was etched by dry etching with a mixed gas of Cl ₂ and O ₂ (Cl ₂ : O ₂ = 4: 1) to form the auxiliary light shielding film pattern 20b. (FIG. 8 (7)).
Next, the resist pattern 110b is peeled off, subjected to predetermined cleaning, and for binary transfer having a light-shielding portion (light-shielding band) 80 composed of the auxiliary light-shielding film pattern 20b and the portion of the light-shielding film pattern 10a therebelow. A mask was obtained (FIG. 8 (8)).

  With regard to the binary transfer mask of this example (1-3), with ArF exposure light, the problem of the electromagnetic field (EMF) effect that becomes a problem in the generation after DRAM half pitch (hp) 32 nm in the design specification of the semiconductor device. On the other hand, it was confirmed that a transfer mask having a sufficient improvement effect and practicality can be provided.

  In the transfer mask manufacturing example, the resist pattern 100a is peeled and removed after the auxiliary light shielding film pattern 20a is formed. However, the resist pattern 100a can be peeled and removed after the light shielding film pattern 10a is formed. Further, in the dry etching of the light shielding film 10, two layers of tantalum oxide of the surface antireflection layer 12 and tantalum nitride of the light shielding layer 11 can be etched at once using the above-mentioned fluorine-based gas.

Examples (1-4) to (1-6)
In Examples (1-4) to (1-6), the etching mask (hard mask) film 30 was formed on the auxiliary light shielding film 20 in Examples (1-1) to (1-3). Is the same as in Examples (1-1) to (1-3).
In Examples (1-4) to (1-6), as shown in FIG. 2, MoSiON is used as an etching mask film 30 on each auxiliary light shielding film 20 in Examples (1-1) to (1-3). Each film was formed.
Specifically, the same MoSiON film as that used for the surface antireflection layer 12 was formed to a thickness of 10 nm, and the etching mask film 30 was formed.
Next, HMDS (hexamethyldisilazane) evaporated using nitrogen gas was brought into contact with the surface of the etching mask film 30 to form a very thin adhesion improving layer 60 made of an HMDS layer. The HMDS layer is a hydrophobic surface layer and improves the adhesion of the resist.

In the binary mask blank of this example (1-4) shown in FIG. 2, the light shielding film 10 includes a light shielding layer 11 made of MoSiCH whose Mo content in the film is 19.8 atomic%, and Mo content in the film. It was set as the laminated structure of the surface antireflection layer 12 which consists of MoSiON whose quantity is 2.6 atomic%. The light shielding film 10 has a thickness of 30 nm and an optical density of 2.0.
The auxiliary light shielding film 20 is made of CrOCN having a Cr content of 33 atomic% in the film, and has an optical density of 0.8 with a film thickness of 30 nm.
On top of that, an etching mask film 30 made of MoSiON having a Mo content of 2.6 atomic% in the film and having a thickness of 10 nm and a very thin adhesion improving layer 60 made of an HMDS layer are provided.

In the binary mask blank of this example (1-5) shown in FIG. 2, the light shielding film 10 includes a light shielding layer 11 made of MoSiCH having a Mo content of 32.3 atomic%, and a Mo content in the film. It was set as the laminated structure of the surface antireflection layer 12 which consists of MoSiON whose quantity is 2.6 atomic%. The light shielding film 10 has a thickness of 30 nm and an optical density of 2.0.
The auxiliary light shielding film 20 is made of CrOCN having a Cr content of 33 atomic% in the film, and has an optical density of 0.8 with a film thickness of 30 nm.
On top of that, an etching mask film 30 made of MoSiON having a Mo content of 2.6 atomic% in the film and having a thickness of 10 nm and a very thin adhesion improving layer 60 made of an HMDS layer are provided.

In the binary mask blank of this example (1-6) shown in FIG. 2, the light shielding film 10 includes a light shielding layer 11 made of TaN having an N content of 7 atomic% in the film, and 58 atoms of O in the film. %, A laminated structure of the surface antireflection layer 12 made of TaO. The light shielding film 10 has a thickness of 36 nm and an optical density of 2.0.
The auxiliary light shielding film 20 is made of CrOCN having a Cr content of 33 atomic% in the film, and has an optical density of 0.8 with a film thickness of 30 nm.
On top of that, an etching mask film 30 made of MoSiON having a Mo content of 2.6 atomic% in the film and having a thickness of 10 nm and a very thin adhesion improving layer 60 made of an HMDS layer are provided.

In the embodiments (1-4) to (1-6), the light shielding film 10 is thinned to the limit of the transfer contrast. The optical density required for the light shielding band is obtained by stacking the light shielding film 10 and the auxiliary light shielding film 20.
In the embodiments (1-4) to (1-6), the auxiliary light shielding is performed as compared with the Cr-based auxiliary light shielding film 20 (also serving as an etching mask) of the above embodiments (1-1) to (1-3). Since the film and the etching mask film are divided into dedicated films, the etching mask film 30 can be thinned, and thereby the resist can be thinned.

(Preparation of transfer mask)
Using the binary mask blanks of Examples (1-4) to (1-6), binary transfer masks of Examples (1-4) to (1-6) were produced.
Specifically, a chemically amplified positive resist 100 (PRL009: manufactured by Fuji Film Electronics Materials) for electron beam drawing (exposure) is formed on the adhesion improving layer 60 of the mask blank by a spin coating method to a film thickness of 75 nm. It applied so that it might become (FIG. 2, FIG. 9 (1)).
Next, after drawing a desired pattern on the resist film 100 using an electron beam drawing apparatus, the resist film 100 was developed with a predetermined developer to form a resist pattern 100a (FIG. 9B).
Next, using the resist pattern 100a as a mask, the adhesion improving layer 60 and the etching mask film 30 were dry-etched to form an etching mask film pattern 30a (FIG. 9 (3)). A mixed gas of SF ₆ and He was used as the dry etching gas.
Next, the remaining resist pattern 100a and the pattern of the adhesion improving layer 60 were peeled and removed with a chemical solution.
Next, the auxiliary light shielding film 20 was dry-etched using the etching mask film pattern 30a as a mask to form the auxiliary light shielding film pattern 20a (FIG. 9 (4)). As a dry etching gas, a mixed gas of Cl ₂ and O ₂ (Cl ₂ : O ₂ = 4: 1) was used.
Next, using the etching mask film pattern 30a and the auxiliary light shielding film pattern 20a as a mask, the light shielding film 10 is dry-etched using a mixed gas of SF ₆ and He to form the light shielding film pattern 10a (FIG. 9 (5). )). At this time, the etching mask film pattern 30a was also etched and removed at the same time.
The subsequent steps are the same as the steps of FIGS. 8 (5) to (8) in the above embodiments (1-1) to (1-3), and thus the description thereof is omitted.
With respect to the binary transfer masks of the embodiments (1-4) to (1-6), an electromagnetic field (ArF exposure light) that causes problems in generations after DRAM half pitch (hp) 32 nm, which is a semiconductor device design specification. It has been confirmed that a transfer mask having a sufficient improvement effect and practicality can be provided for the problem of the EMF) effect.

Examples (1-7) to (1-9)
As shown in FIG. 3, Examples (1-7) to (1-9) are the etching masks (hard masks) on the auxiliary light shielding film 20 in the above Examples (1-1) to (1-3). ) A film 30 is formed, and the same as the embodiments (1-4) to (1-6) except that the second etching mask (hard mask) film 40 is formed on the etching mask film 30.
In Examples (1-7) to (1-9), a MoSiON film is formed as an etching mask film 30 on each auxiliary light shielding film 20 in Examples (1-1) to (1-3). A CrOCN film was formed as a second etching mask film 40 on each of them.
Specifically, the same MoSiON film as that used for the surface antireflection layer 12 was formed to a thickness of 10 nm, and the etching mask film 30 was formed.
Next, the same CrOCN film as that used for the auxiliary light shielding film 20 was formed to a thickness of 10 nm, and the second etching mask film 40 was formed.

In the binary mask blank of the present example (1-7) shown in FIG. 3, the light shielding film 10 includes a light shielding layer 11 made of MoSiCH whose Mo content in the film is 19.8 atomic%, and Mo content in the film. It was set as the laminated structure of the surface antireflection layer 12 which consists of MoSiON whose quantity is 2.6 atomic%. The light shielding film 10 has a thickness of 30 nm and an optical density of 2.0.
The auxiliary light shielding film 20 is made of CrOCN having a Cr content of 33 atomic% in the film, and has an optical density of 0.8 with a film thickness of 30 nm.
On top of that, an etching mask film 30 made of MoSiON having a Mo content of 2.6 atomic% in the film and having a thickness of 10 nm is provided.
A second etching mask film 40 made of CrOCN having a Cr content of 33 atomic% and having a thickness of 10 nm is formed thereon.

In the binary mask blank of this example (1-8) shown in FIG. 3, the light shielding film 10 includes a light shielding layer 11 made of MoSiCH whose Mo content in the film is 32.3 atomic%, and Mo content in the film. It was set as the laminated structure of the surface antireflection layer 12 which consists of MoSiON whose quantity is 2.6 atomic%. The light shielding film 10 has a thickness of 30 nm and an optical density of 2.0.
The auxiliary light shielding film 20 is made of CrOCN having a Cr content of 33 atomic% in the film, and has an optical density of 0.8 with a film thickness of 30 nm.
On top of that, an etching mask film 30 made of MoSiON having a Mo content of 2.6 atomic% in the film and having a thickness of 10 nm is provided.
A second etching mask film 40 made of CrOCN having a Cr content of 33 atomic% and having a thickness of 10 nm is formed thereon.

In the binary mask blank of this example (1-9) shown in FIG. 3, the light shielding film 10 includes a light shielding layer 11 made of TaN having an N content of 7 atomic% in the film, and 58 atoms of O in the film. %, A laminated structure of the surface antireflection layer 12 made of TaO. The light shielding film 10 has a thickness of 36 nm and an optical density of 2.0.
The auxiliary light shielding film 20 is made of CrOCN having a Cr content of 33 atomic% in the film, and has an optical density of 0.8 with a film thickness of 30 nm.
On top of that, an etching mask film 30 made of MoSiON having a Mo content of 2.6 atomic% in the film and having a thickness of 10 nm is provided.
A second etching mask film 40 made of CrOCN having a Cr content of 33 atomic% and having a thickness of 10 nm is formed thereon.

In the embodiments (1-7) to (1-9), the light shielding film 10 is thinned to the limit of the transfer contrast. The optical density required for the light shielding band is obtained by stacking the light shielding film 10 and the auxiliary light shielding film 20.
In the embodiments (1-7) to (1-9), auxiliary light shielding is performed as compared with the Cr-based auxiliary light shielding film 20 (also serving as an etching mask) of the above embodiments (1-1) to (1-3). Since the film and the etching mask film are separated as dedicated films, the etching mask film 30 can be thinned, and the resist can be thinned.
Further, in the embodiments (1-7) to (1-9), the embodiments (1-4) to (1-6) are adopted by adopting the chromium-based second etching mask film 40. In comparison, it is possible to reduce the thickness of the resist and improve the adhesion of the resist.

(Preparation of transfer mask)
Using the binary mask blanks of Examples (1-7) to (1-9), binary transfer masks of Examples (1-7) to (1-9) were produced.
Specifically, a chemical amplification type positive resist 100 (PRL009: manufactured by Fuji Film Electronics Materials) for electron beam drawing (exposure) is formed on the second etching mask film 40 of the mask blank by a spin coat method. It apply | coated so that it might become 50 nm (FIG. 3, FIG. 10 (1)).
Next, after drawing a desired pattern on the resist film 100 using an electron beam drawing apparatus, the resist film 100 was developed with a predetermined developer to form a resist pattern 100a (FIG. 10B).
Next, using the resist pattern 100a as a mask, the second etching mask film 40 was dry-etched to form a second etching mask film pattern 40a (FIG. 10 (3)). As a dry etching gas, a mixed gas of Cl ₂ and O ₂ (Cl ₂ : O ₂ = 4: 1) was used.
Next, the remaining resist pattern 100a was peeled off with a chemical solution.
Next, using the second etching mask film pattern 40a as a mask, the etching mask film 30 was dry-etched to form an etching mask film pattern 30a (FIG. 10 (4)). A mixed gas of SF ₆ and He was used as the dry etching gas.
Next, the auxiliary light shielding film 20 was dry-etched using the second etching mask film pattern 40a and the etching mask film pattern 30a as a mask to form the auxiliary light shielding film pattern 20a (FIG. 10 (5)). As a dry etching gas, a mixed gas of Cl ₂ and O ₂ (Cl ₂ : O ₂ = 4: 1) was used. At this time, the second etching mask film pattern 40a was also etched and removed.
Next, using the etching mask film pattern 30a and the auxiliary light shielding film pattern 20a as a mask, the light shielding film 10 is dry-etched using a mixed gas of SF ₆ and He to form a light shielding film pattern 10a (FIG. 10 (6)). )). At this time, the etching mask film pattern 30a was also etched and removed.
The subsequent steps are the same as the steps of FIGS. 8 (5) to (8) in the above embodiments (1-1) to (1-3), and thus the description thereof is omitted.
With respect to the binary transfer masks of Examples (1-7) to (1-9), an electromagnetic field (problem with generations after DRAM half-pitch (hp) 32 nm, which is a semiconductor device design specification), is used with ArF exposure light. It has been confirmed that a transfer mask having a sufficient improvement effect and practicality can be provided for the problem of the EMF) effect.

Examples (1-10) to (1-12)
As shown in FIG. 4, Examples (1-10) to (1-12) include etching stopper / mask layer 21 on light shielding film 10 in Examples (1-1) to (1-3). The auxiliary light shielding film 20 having a laminated structure of the auxiliary light shielding layer 22 was formed (the structure of the auxiliary light shielding film 20, the formation position, material, and film thickness of each layer were changed), and the adhesion improving layer 60 was formed thereon Is the same as in Examples (1-1) to (1-3).
In Examples (1-10) to (1-12), a CrOCN film is formed as an etching stopper and mask layer 21 on each light shielding film 10 in Examples (1-1) to (1-3). A MoSiCH film was formed as an auxiliary light shielding layer 22 thereon, and an HMDS layer was formed as an adhesion improving layer 60 thereon.
Specifically, the same CrOCN film as that used for the auxiliary light shielding film 20 of Example 1-1 was formed to a thickness of 10 nm, and the etching stopper / mask layer 21 was formed.
Next, the same MoSiCH film as that used for the light shielding layer 11 of Example 1-1 was formed to a thickness of 15 nm, and the auxiliary light shielding layer 22 was formed.
Next, HMDS (hexamethyldisilazane) evaporated using nitrogen gas was brought into contact with the surface of the auxiliary light shielding layer 22 to form a very thin adhesion improving layer 60 made of an HMDS layer. The HMDS layer is a hydrophobic surface layer and improves the adhesion of the resist.

In the binary mask blank of this example (1-10) shown in FIG. 4, the light shielding film 10 includes a light shielding layer 11 made of MoSiCH whose Mo content in the film is 19.8 atomic%, and Mo content in the film. It was set as the laminated structure of the surface antireflection layer 12 which consists of MoSiON whose quantity is 2.6 atomic%. The light shielding film 10 has a thickness of 30 nm and an optical density of 2.0.
On top of that, an etching stopper / mask layer 21 made of CrOCN having a Cr content of 33 atomic% in the film and having a thickness of 10 nm is provided. Further, the auxiliary light shielding layer 22 having a film thickness of 15 nm is formed of MoSiCH having a Mo content of 19.8 atomic%. The auxiliary light-shielding film 20 having a film thickness of 25 nm is formed by a laminated structure of the etching stopper / mask layer 21 and the auxiliary light-shielding layer 22, and the optical density in the laminated structure is 0.8.
In addition, the HMDS layer having a very thin thickness is provided as the adhesion improving layer 60.

In the binary mask blank of this example (1-11) shown in FIG. 4, the light shielding film 10 includes a light shielding layer 11 made of MoSiCH whose Mo content in the film is 32.3 atomic%, and Mo content in the film. It was set as the laminated structure of the surface antireflection layer 12 which consists of MoSiON whose quantity is 2.6 atomic%. The light shielding film 10 has a thickness of 30 nm and an optical density of 2.0.
On top of that, an etching stopper / mask layer 21 made of CrOCN having a Cr content of 33 atomic% in the film and having a thickness of 10 nm is provided. Further, the auxiliary light shielding layer 22 having a film thickness of 15 nm is formed of MoSiCH having a Mo content of 19.8 atomic%. The auxiliary light-shielding film 20 having a film thickness of 25 nm is formed by a laminated structure of the etching stopper / mask layer 21 and the auxiliary light-shielding layer 22, and the optical density in the laminated structure is 0.8.
In addition, the HMDS layer having a very thin thickness is provided as the adhesion improving layer 60.

In the binary mask blank of this example (1-12) shown in FIG. 4, the light shielding film 10 includes a light shielding layer 11 made of TaN having an N content of 7 atomic% in the film, and 58 atoms of O in the film. %, A laminated structure of the surface antireflection layer 12 made of TaO. The light shielding film 10 has a thickness of 36 nm and an optical density of 2.0.
On top of that, an etching stopper / mask layer 21 made of CrOCN having a Cr content of 33 atomic% in the film and having a thickness of 10 nm is provided. Further, the auxiliary light shielding layer 22 having a film thickness of 15 nm is formed of MoSiCH having a Mo content of 19.8 atomic%. The auxiliary light-shielding film 20 having a film thickness of 25 nm is formed by a laminated structure of the etching stopper / mask layer 21 and the auxiliary light-shielding layer 22, and the optical density in the laminated structure is 0.8.
In addition, the HMDS layer having a very thin thickness is provided as the adhesion improving layer 60.

In the embodiments (1-10) to (1-12), the light shielding film 10 is thinned to the limit of the transfer contrast. The optical density required for the light shielding band is obtained by stacking the light shielding film 10 and the auxiliary light shielding film 20.
In the embodiments of the above Examples (1-10) to (1-12), the light shielding film is compared with the Cr-based auxiliary light shielding film 20 (also serving as an etching mask) of the above Examples (1-1) to (1-3). Thus, the etching stopper / mask layer 21 can be made thinner with respect to 10. Thereby, higher etching accuracy of the light shielding film 10 is obtained.
In the embodiments of the above Examples (1-10) to (1-12), compared with the Cr-based auxiliary light shielding film 20 of the above Examples (1-1) to (1-3), compared with the same optical density, The auxiliary light shielding film 20 can be thinned. The thin auxiliary light shielding film 20 can reduce the thickness of the resist as compared with the embodiments (1-1) to (1-3).

(Preparation of transfer mask)
Using the binary mask blanks of Examples (1-10) to (1-12), binary transfer masks of Examples (1-10) to (1-12) were prepared.
Specifically, a chemically amplified positive resist 100 (PRL009: manufactured by Fuji Film Electronics Materials) for electron beam drawing (exposure) is deposited on the adhesion improving layer 60 of the mask blank by a spin coating method to a film thickness of 75 nm. (FIG. 4, FIG. 11 (1)).
Next, a desired pattern was drawn on the resist film 100 using an electron beam drawing apparatus, and then developed with a predetermined developer to form a resist pattern 100a (FIG. 11 (2)).
Next, the auxiliary light shielding layer 22 was dry-etched using the resist pattern 100a as a mask to form the auxiliary light shielding layer pattern 22a (FIG. 11 (3)). A mixed gas of SF ₆ and He was used as the dry etching gas. The adhesion improving layer 60 is also patterned by dry etching at the same time.
Next, the remaining resist pattern 100a was peeled off with a chemical solution. At this time, the adhesion improving layer 60 is also peeled and removed at the same time.
Next, the etching stopper / mask layer 21 was dry-etched using the auxiliary light shielding layer pattern 22a as a mask to form an etching stopper / mask layer pattern 21a (FIG. 11 (4)). As a dry etching gas, a mixed gas of Cl ₂ and O ₂ (Cl ₂ : O ₂ = 4: 1) was used.
Next, a resist film 110 of an electron beam drawing (exposure) positive resist (FEP171: manufactured by Fuji Film Electronics Materials) was applied onto the substrate so as to have a film thickness of 200 [nm] by spin coating. (FIG. 11 (5)).
Next, the resist film 110 was subjected to drawing exposure with a pattern of a light-shielding portion (light-shielding band) using an electron beam drawing apparatus, and developed with a predetermined developer to form a resist pattern 110b (FIG. 11 (6)). ).
Next, using the etching stopper / mask layer pattern 21a as a mask, the light shielding film 10 was dry-etched using a mixed gas of SF ₆ and He to form the light shielding film pattern 10a (FIG. 11 (7)). . At the same time, the auxiliary light shielding layer pattern 22a was etched by dry etching using the resist pattern 110b as a mask to form the auxiliary light shielding layer pattern 22b (FIG. 11 (7)).
Next, using the resist pattern 110b and the auxiliary light shielding layer pattern 22b as a mask, the etching stopper / mask layer pattern 21a is etched by dry etching with a mixed gas of Cl ₂ and O ₂ (Cl ₂ : O ₂ = 4: 1). Then, an etching stopper / mask layer pattern 21b was formed (FIG. 11 (8)).
Next, the resist pattern 110b is peeled off, subjected to predetermined cleaning, and a transfer mask having a light shielding portion (light shielding band) 80 composed of the auxiliary light shielding film pattern 20b and the portion of the light shielding film pattern 10a below the auxiliary light shielding film pattern 20b. (FIG. 11 (9)).
As described above, the binary transfer masks of Examples (1-10) and (1-11) were produced.

In Example (1-12), the light shielding film 10 is dry-etched using the etching stopper / mask layer pattern 21a as a mask in FIG. 10a was formed. At this time, two layers were etched simultaneously using a mixed gas of CHF ₃ and He as a dry etching gas for the tantalum oxide (TaO) layer 12 and the tantalum nitride (TaN) layer 11. At the same time, the auxiliary light shielding layer pattern 22a was etched by dry etching using the resist pattern 110b as a mask to form the auxiliary light shielding layer pattern 22b (FIG. 11 (7)).
A binary transfer mask of this example (1-12) was produced in the same manner as in the above example (1-10) except for the above steps.
With respect to the binary transfer masks of Examples (1-10) to (1-12), the electromagnetic field (problem with generations after DRAM half pitch (hp) 32 nm, which is the design specification of the semiconductor device), is ArF exposure light. It has been confirmed that a transfer mask having a sufficient improvement effect and practicality can be provided for the problem of the EMF) effect.

Examples (1-13) to (1-15)
In Examples (1-13) to (1-15), as shown in FIG. 5, in Examples (1-1) to (1-3), an etching stopper / mask layer 21 was formed on the light shielding film 10. The auxiliary light shielding layer 22 is formed thereon (the structure of the auxiliary light shielding film 20, the formation position of each layer, the material and the film thickness are changed), and the etching mask film 70 is formed thereon. The same as in Examples (1-4) to (1-6).
In Examples (1-13) to (1-15), a CrOCN film is formed as an etching stopper and mask layer 21 on each light shielding film 10 in Examples (1-1) to (1-3). A MoSiCH film was formed as an auxiliary light shielding layer 22 thereon, and a CrOCN film was formed as an etching mask film 70 thereon.
Specifically, the same CrOCN film as that used for the auxiliary light shielding film 20 of Example 1-1 was formed to a thickness of 10 nm, and the etching stopper / mask layer 21 was formed.
Next, the same MoSiCH film as that used for the light shielding layer 11 of Example 1-1 was formed to a thickness of 15 nm, and the auxiliary light shielding layer 22 was formed.
Next, the same CrOCN film as that used for the auxiliary light shielding film 20 of Example 1-1 was formed to a thickness of 10 nm, and an etching mask film 70 was formed.

In the binary mask blank of this example (1-13) shown in FIG. 5, the light shielding film 10 includes a light shielding layer 11 made of MoSiCH whose Mo content in the film is 19.8 atomic%, and Mo content in the film. It was set as the laminated structure of the surface antireflection layer 12 which consists of MoSiON whose quantity is 2.6 atomic%. The light shielding film 10 has a thickness of 30 nm and an optical density of 2.0.
On top of that, an etching stopper / mask layer 21 made of CrOCN having a Cr content of 33 atomic% in the film and having a thickness of 10 nm is provided. Further, the auxiliary light shielding layer 22 having a film thickness of 15 nm is formed of MoSiCH having a Mo content of 19.8 atomic%. The auxiliary light-shielding film 20 having a film thickness of 25 nm is formed by a laminated structure of the etching stopper / mask layer 21 and the auxiliary light-shielding layer 22, and the optical density in the laminated structure is 0.8.
On top of this, an etching mask film 70 made of CrOCN having a Cr content of 33 atomic% in the film and having a thickness of 10 nm is provided.

In the binary mask blank of this example (1-14) shown in FIG. 5, the light shielding film 10 has a light shielding layer 11 made of MoSiCH whose Mo content in the film is 33 atomic%, and a Mo content in the film. It was set as the laminated structure of the surface antireflection layer 12 which consists of MoSiON which is 2.6 atomic%. The light shielding film 10 has a thickness of 30 nm and an optical density of 2.0.
On top of that, an etching stopper / mask layer 21 made of CrOCN having a Cr content of 33 atomic% in the film and having a thickness of 10 nm is provided. Further, the auxiliary light shielding layer 22 having a film thickness of 15 nm is formed of MoSiCH having a Mo content of 19.8 atomic%. The auxiliary light-shielding film 20 having a film thickness of 25 nm is formed by a laminated structure of the etching stopper / mask layer 21 and the auxiliary light-shielding layer 22, and the optical density in the laminated structure is 0.8.
On top of this, an etching mask film 70 made of CrOCN having a Cr content of 33 atomic% in the film and having a thickness of 10 nm is provided.

In the binary mask blank of this example (1-15) shown in FIG. 5, the light shielding film 10 includes a light shielding layer 11 made of TaN having an N content of 7 atomic% in the film, and 58 atoms of O in the film. %, A laminated structure of the surface antireflection layer 12 made of TaO. The light shielding film 10 has a thickness of 36 nm and an optical density of 2.0.
On top of that, an etching stopper / mask layer 21 made of CrOCN having a Cr content of 33 atomic% in the film and having a thickness of 10 nm is provided. Further, the auxiliary light shielding layer 22 having a film thickness of 15 nm is formed of MoSiCH having a Mo content of 19.8 atomic%. The auxiliary light-shielding film 20 having a film thickness of 25 nm is formed by a laminated structure of the etching stopper / mask layer 21 and the auxiliary light-shielding layer 22, and the optical density in the laminated structure is 0.8.
On top of this, an etching mask film 70 made of CrOCN having a Cr content of 33 atomic% in the film and having a thickness of 10 nm is provided.

In the embodiments (1-13) to (1-15), the light shielding film 10 is thinned to the limit of the transfer contrast. The optical density required for the light shielding band is obtained by a laminated structure of the light shielding film 10 and the auxiliary light shielding film 20.
In the embodiments of the above Examples (1-13) to (1-15), the light shielding film is compared with the Cr-based auxiliary light shielding film 20 (also serving as an etching mask) of the above Examples (1-1) to (1-3). Thus, the etching stopper / mask layer 21 can be made thinner with respect to 10. Thereby, higher etching accuracy of the light shielding film 10 is obtained.
In the embodiments of the above Examples (1-13) to (1-15), compared with the Cr-based auxiliary light shielding film 20 of the above Examples (1-1) to (1-3), compared with the same optical density, The auxiliary light shielding film 20 can be thinned. The thin auxiliary light shielding film 20 can reduce the thickness of the resist as compared with the embodiments (1-1) to (1-3).
Further, by employing the chromium-based etching mask film 70, the resist can be made thinner and the adhesion of the resist is improved as compared with the embodiments (1-10) to (1-12).

(Preparation of transfer mask)
Using the binary mask blanks of Examples (1-13) to (1-15), binary masks of Examples (1-13) to (1-15) were produced.
Specifically, a chemically amplified positive resist 100 (PRL009: manufactured by Fuji Film Electronics Materials) for electron beam drawing (exposure) is formed on the etching mask film 70 of the mask blank to a film thickness of 50 nm by spin coating. It applied so that it might become (FIG. 5, FIG. 12 (1)).
Next, a desired pattern was drawn on the resist film 100 using an electron beam drawing apparatus, and then developed with a predetermined developer to form a resist pattern 100a (FIG. 12 (2)).
Next, using the resist pattern 100a as a mask, the etching mask film 70 was dry-etched to form an etching mask film pattern 70a (FIG. 12 (3)). As a dry etching gas, a mixed gas of Cl ₂ and O ₂ (Cl ₂ : O ₂ = 4: 1) was used.
Next, the remaining resist pattern 100a was peeled off with a chemical solution.
Next, the auxiliary light shielding layer 22 was dry-etched using the etching mask film pattern 70a as a mask to form the auxiliary light shielding layer pattern 22a (FIG. 12 (4)). A mixed gas of SF ₆ and He was used as the dry etching gas.
Next, using the auxiliary light shielding layer pattern 22a as a mask, the etching stopper / mask layer 21 was dry etched to form an etching stopper / mask layer pattern 21a (FIG. 12 (5)). As a dry etching gas, a mixed gas of Cl ₂ and O ₂ (Cl ₂ : O ₂ = 4: 1) was used. At this time, the etching mask film 70 was peeled and removed simultaneously by etching.
Next, a resist film 110 of an electron beam drawing (exposure) positive resist (FEP171: manufactured by Fuji Film Electronics Materials) was applied onto the substrate so as to have a film thickness of 200 [nm] by spin coating. (FIG. 12 (6)).
Next, the resist film 110 was subjected to drawing exposure with a pattern of a light shielding portion (light shielding band) using an electron beam drawing apparatus, and developed with a predetermined developer to form a resist pattern 110b (FIG. 12 (7)). ).
Next, using the etching stopper / mask layer pattern 21a as a mask, the light shielding film 10 was dry-etched using a mixed gas of SF ₆ and He to form the light shielding film pattern 10a (FIG. 12 (8)). . At the same time, the auxiliary light shielding layer pattern 22a was etched by dry etching using the resist pattern 110b as a mask to form the auxiliary light shielding layer pattern 22b (FIG. 12 (8)).
Next, using the resist pattern 110b and the auxiliary light shielding layer pattern 22b as a mask, the etching stopper / mask layer pattern 21a is etched by dry etching with a mixed gas of Cl ₂ and O ₂ (Cl ₂ : O ₂ = 4: 1). Then, an etching stopper / mask layer pattern 21b was formed (FIG. 12 (9)).
Next, the resist pattern 110b is peeled off, subjected to predetermined cleaning, and a transfer mask having a light shielding portion (light shielding band) 80 composed of the auxiliary light shielding film pattern 20b and the portion of the light shielding film pattern 10a below the auxiliary light shielding film pattern 20b. (FIG. 12 (10)).
As described above, the binary transfer masks of Examples (1-13) and (1-14) were produced.

In Example (1-15), the light shielding film 10 is dry-etched using the etching stopper / mask layer pattern 21a as a mask in FIG. 10a was formed. At this time, two layers were etched simultaneously using a mixed gas of CHF ₃ and He as a dry etching gas for the tantalum oxide (TaO) layer 12 and the tantalum nitride (TaN) layer 11. At the same time, the auxiliary light shielding layer pattern 22a was etched by dry etching using the resist pattern 110b as a mask to form the auxiliary light shielding layer pattern 22b (FIG. 12 (8)).
A binary transfer mask of Example (1-15) was prepared in the same manner as Example (1-13) except for the above steps.
With respect to the binary transfer masks of the embodiments (1-13) to (1-15), the electromagnetic field (problem with generations after DRAM half pitch (hp) 32 nm, which is the design specification of the semiconductor device, is ArF exposure light). It has been confirmed that a transfer mask having a sufficient improvement effect and practicality can be provided for the problem of the EMF) effect.

Examples (2-1) to (2-9)
(Manufacture of mask blank)
In Examples (2-1) to (2-9), the thickness of the auxiliary light shielding film 20 is set to 35 nm and the optical density of the auxiliary light shielding film 20 is set to 1 in Examples (1-1) to (1-9). .1 and the same as in Examples (1-1) to (1-9) except that a binary mask blank used for double exposure was used.

(Preparation of transfer mask)
Using the binary mask blanks of the examples (2-1) to (2-9), the examples (2-1) to (1-9) to (1-9) to (1-9) were performed in the same manner as the examples (1-1) to (1-9). The binary transfer mask of 2-9) was produced.
With regard to the binary transfer masks of Examples (2-1) to (2-9), an electromagnetic field (ArF exposure light) that causes a problem in generations after DRAM half pitch (hp) 32 nm, which is a semiconductor device design specification. It has been confirmed that a transfer mask having a sufficient improvement effect and practicality can be provided for the problem of the EMF) effect.

Examples (2-10) to (2-15)
(Manufacture of mask blank)
In Examples (2-10) to (2-15), MoSiCH in which the Mo content in the auxiliary light shielding layer 22 is 32.3 atomic% in Examples (1-10) to (1-15) Examples (1-10) to (1-15) except that the optical density of the auxiliary light-shielding film 20 was set to 1.1 by using a film and the thickness was 20 nm to obtain a binary mask blank used for double exposure. ).

(Preparation of transfer mask)
Using the binary mask blanks of Examples (2-10) to (2-15), in the same manner as Examples (1-10) to (1-15), Examples (2-10) to ( The binary mask of 2-15) was produced.
With respect to the binary transfer masks of the present embodiments (2-10) to (2-15), the electromagnetic fields (problems in the generation after the DRAM half pitch (hp) 32 nm in the design specifications of the semiconductor device with ArF exposure light) It has been confirmed that a transfer mask having a sufficient improvement effect and practicality can be provided for the problem of the EMF) effect.

Examples (3-1), (3-2), (3-4), (3-5), (3-7), (3-8), (3-10), (3-11), (3-13), (3-14)
(Manufacture of mask blank)
Examples (3-1), (3-2), (3-4), (3-5), (3-7), (3-8), (3-10), (3-11), (3-13) and (3-14) are the examples (1-1), (1-2), (1-4), (1-5), (1-7), (1-8) , (1-10), (1-11), (1-13), (1-14), the thickness of the light shielding film 10 is set to 35 nm (the thickness of the light shielding layer 11 is set to 20 nm). Example (1-1), (1-2), (1-4), (1-5), except that the optical density of 10 was 2.3 and a binary mask blank used for double exposure was used. The same as (1-7), (1-8), (1-10), (1-11), (1-13), and (1-14).

(Preparation of transfer mask)
Using the binary mask blanks of the above Examples (3-1) to (3-14), the Examples (3-1) to (1) to (1) to (1-14) were performed in the same manner as the above Examples (1-1) to (1-14). A binary transfer mask of (3-14) was produced.
Regarding the binary masks of the examples (3-1) to (3-14), the electromagnetic field (EMF) which is a problem in the generation after the DRAM half pitch (hp) 32 nm in the design specifications of the semiconductor device with ArF exposure light. It was confirmed that a transfer mask having a sufficient improvement effect and practicality can be provided for the problem of the effect.

Example (3-3), (3-6), (3-9), (3-12), (3-15)
(Manufacture of mask blank)
Examples (3-3), (3-6), (3-9), (3-12), and (3-15) are examples of (1-3), (1-6), (1- 9) In (1-12) and (1-15), the optical density of the light shielding film 10 is set to 2.3 by setting the thickness of the light shielding film 10 to 40 nm (the thickness of the light shielding layer 11 is 30 nm). Except for the binary mask blank used for double exposure, the same as in Examples (1-3), (1-6), (1-9), (1-12), and (1-15) .

(Preparation of transfer mask)
Using the binary mask blanks of Examples (3-3) to (3-15), Examples (3-3) to (1-3) to (1-15) were performed in the same manner as Examples (1-1) to (1-15). A binary transfer mask of (3-15) was produced.
With respect to the binary transfer masks of Examples (3-3) to (3-15), an electromagnetic field (EMF) which becomes a problem in the generation after the DRAM half pitch (hp) 32 nm in the design specification of the semiconductor device with ArF exposure light. ) It was confirmed that a transfer mask having a sufficient improvement effect and practicality can be provided for the problem of effect.

Example (4-1)
(Light shielding film design)
Of various MoSi-based film materials whose refractive index n and extinction coefficient k have been measured in advance, a MoSi film (n = 2.4, k = 2) is used as the light-shielding film 10 as a film material. .9), a MoSiON film (n = 2.1, k = 0.3) was selected as the surface antireflection layer 12, and the following optical simulation was performed.
In this optical simulation, for the selected material, the film thickness condition of the light shielding layer 11 is varied in the range of 10 nm to 40 nm, and the film thickness condition of the surface antireflection layer 12 is varied in the range of 4 nm to 20 nm. The entire optical density (OD) and surface reflectance (R%) of the light shielding film 10 were calculated. A graph plotting the calculated results is shown in FIG.

  In FIG. 13, the horizontal axis of the graph is the film thickness of the light shielding layer 11, and the vertical axis is the film thickness of the surface antireflection layer 12. The optical density is divided into areas at 2.0, 2.8, and 3.0 boundary lines, and the surface reflectance is divided into areas at 30%, 25%, and 20% boundaries. Has been. Further, the light shielding film extends from the point where the thickness of the light shielding layer 11 is 36 nm and the thickness of the surface antireflection layer 12 is 4 nm to the point where the thickness of the light shielding layer 11 is 20 nm and the thickness of the surface antireflection layer 12 is 20 nm. The boundary line with which the total film thickness of 10 is 40 nm is drawn.

It can be said that the optical density of the light shielding film 10 tends to increase as it goes from the left side to the right side of the graph, that is, as the thickness of the light shielding layer 11 increases. About the surface reflectance of the light shielding film 10, it can be said that it tends to become low as the film thickness of the surface antireflection layer 12 becomes thicker from the lower side of the graph to the upper side. However, both the optical density and the surface reflectance are affected by light interference caused by multiple reflections between the light shielding layer 11 and the surface antireflection layer 12, so that the optical simulation is not a simple linear relationship. Therefore, it can be said that it is necessary to study strictly. In addition, the area | region where the total film thickness of the light shielding film 10 in a graph becomes 40 nm or less is as follows.
The region is on the left side of the boundary line.

  In this example (4-1), the threshold value of the surface reflectance, which is one of the selection conditions for the light shielding film 10, is set to 30% or less. Even if the surface reflectance is greater than 30% and 40% or less, there are cases where exposure transfer can be performed normally. However, depending on the specifications of the exposure apparatus, the characteristics of the resist on the wafer to be transferred, and the like, if the surface reflectance is higher than 30%, the accuracy of exposure transfer may decrease. Considering this point, the threshold value of the surface reflectance is set to 30% or less. Hereinafter, the same applies to other embodiments.

  Here, the conditions under which the light-shielding film 10 having an optical density of 2.0 or more, a total film thickness of 40 nm or less, and a surface reflectance of 30% or less can be produced are three conditions P203, P301, and P302 in FIG. Inside the area with vertices. The conditions under which the light-shielding film 10 having an optical density of 2.0 or more, a total film thickness of 40 nm or less, and a surface reflectance of 25% or less can be produced are the three apexes P203, P251, and P252 in FIG. Inside the region having Furthermore, the conditions under which the light-shielding film 10 having an optical density of 2.0 or more, a total film thickness of 40 nm or less, and a surface reflectance of 20% or less can be created are the three apexes P203, P201, and P202 in FIG. Inside the region having In this example (4-1), based on the result of the optical simulation of FIG. 13, a film thickness of the light shielding layer 11 of 24 nm and a film thickness of 10 nm are selected as the surface antireflection layer, respectively, and the optical density is 2.0 or more. The light shielding film 10 having a reflectance of 20% or less was designed.

Next, a transfer mask was prepared with a mask blank using the selected light-shielding film 10, and it was confirmed by optical simulation whether sufficient contrast could be obtained when exposed and transferred to the resist on the wafer. The result is shown in FIG. In the optical simulation of FIG. 14, the light-shielding film 10 having various optical densities (the film thickness of the surface anti-reflection layer 12 is 10 nm) using the materials of the light-shielding layer 11 and the surface anti-reflection layer 12 used in Example (4-1). The contrast in the case of forming the (fixed) is calculated. The transfer pattern formed on the light-shielding film is a DRAM hp 32 nm generation and assumes that double patterning is applied, and a line & space pattern of line: space = 3: 1 = 384 nm: 128 nm is applied to perform a simulation. It was. As a result, it was found that although the optical density was not as high as 2.8, the contrast was as good as 0.8 or higher even at an optical density of 2.0. That is, sufficient contrast can be obtained even with the light shielding film 10 having an optical density of 2.0 designed previously.
The contrast is a relationship between the maximum values Imax and Imin of the light intensity distribution when the exposure light that has passed through the light transmitting portion of the transfer mask forms an image on the resist on the wafer, and contrast = (Imax−Imin) / (Imax + Imin). Hereinafter, the same applies to other embodiments.

Next, it was confirmed by optical simulation whether the EMF bias was sufficiently reduced in the mask blank using the selected light shielding film 10. The result is shown in FIG. In the optical simulation of FIG. 15, the EMF bias is calculated when the light shielding film 10 having various total film thicknesses is formed from the materials of the light shielding layer 11 and the surface antireflection layer 12 used in this example (4-1). ing. The EMF bias on the vertical axis in FIG. 15 is obtained by subtracting the bias calculated by the EMF simulation from the bias calculated by the optical simulation by TMA. That is, the bias amount related to the EMF effect is calculated by subtracting the simulation result considering the EMF effect from the simulation result not considering the EMF effect. The horizontal axis in FIG. 15 is the total thickness of the light shielding film 10. The total thickness of the light shielding film 10 is changed by fixing the surface antireflection layer 12 to 10 nm, which is the previously designed film thickness, and changing the film thickness of the light shielding layer 11. In addition, as the design pattern applied to the optical simulation, the same line and space pattern as that used in the contrast simulation is applied to calculate the respective biases.
As a result, it was found that when the total film thickness of the light shielding film 10 is 40 nm or less, the influence of the EMF effect can be greatly reduced as compared with the conventional light shielding film having a total film thickness of about 60 nm.

(Manufacture of mask blank)
In Example (4-1), a mask blank similar to Example (1-1) was produced except that the light shielding film 10 was replaced with the light shielding film 10 designed from the result of the optical simulation of FIG.
In Example (4-1), a MoSi film (light shielding layer 11) and a MoSiON film (surface antireflection layer 12) were formed as the light shielding film 10 on the translucent substrate 1, respectively.

Specifically, using a DC magnetron sputtering apparatus, using a target of Mo: Si = 21 atomic%: 79 atomic%, and a film made of molybdenum and silicon in an Ar gas atmosphere (Mo: 21 atomic%, Si: 79 Atom%) was formed with a film thickness of 24 nm to form a MoSi film (light shielding layer 11).
Next, using a target of Mo: Si = 4 atomic%: 96 atomic%, in a mixed gas atmosphere of Ar, O ₂ , N _2, and He, a film made of molybdenum, silicon, oxygen, and nitrogen (Mo: 2 atomic%, Si: 37 atomic%, O: 23 atomic%, and N: 38 atomic%) were formed with a film thickness of 10 nm to form a MoSiON film (surface antireflection layer 12).
Next, the substrate was heated (annealed) at 450 ° C. for 30 minutes.

Refractive index n and extinction coefficient k were measured with respect to light shielding film 10 formed on translucent substrate 1 using an optical thin film characteristic measuring device n & k 1280 (manufactured by n & k Technology). As a result, this light-shielding film 10 was confirmed that the light-shielding layer 11 had n = 2.4 and k = 2.9, and the surface antireflection layer 12 had n = 2.1 and k = 0.3. It was. Moreover, the optical density (OD) and the surface reflectance were measured with respect to the light shielding film 10 with a spectrophotometer U-4100 (manufactured by Hitachi High-Technologies Corporation). As a result, this light-shielding film 10 was confirmed to have an optical density of 2.0 with respect to ArF exposure light (wavelength 193 nm) and a surface reflectance of 19.8%. Further, when the optical density was measured after the auxiliary light shielding film 20 was formed, it was confirmed that the optical density with respect to ArF exposure light (wavelength 193 nm) was 2.8 in the laminated structure of the light shielding film 10 and the auxiliary light shielding film 20. It was.
As described above, a binary mask blank on which the auxiliary light shielding film 20 and the light shielding film 10 for ArF excimer laser exposure and single exposure were formed was obtained.

(Preparation of transfer mask)
Using the binary mask blank of this example (4-1), a binary transfer mask of this example (4-1) was produced in the same manner as in the above example (1-1).
Here, for the mask design pattern, prepare the transfer pattern generated by strict correction calculation by EMF simulation as usual and the transfer pattern generated by correction calculation by reducing the calculation load by using TMA simulation, etc. Each transfer pattern was drawn on the resist film 100 of the two binary mask blanks produced previously, and two binary transfer masks were produced.
When the transfer pattern was exposed and transferred to the resist film on the wafer with an exposure apparatus for each of the two binary transfer masks, both patterns could be transferred with high accuracy. It can be confirmed that the mask blank of this example (4-1) can produce a transfer mask having sufficient transfer performance even with a transfer pattern generated by correction calculation using TMA simulation to reduce the calculation load. It was. In addition, even for a maximum of four times of overexposure due to leakage light to the outer peripheral region, the light shielding portion (light shielding band) 80 composed of the auxiliary light shielding film pattern 20b and the light shielding film pattern 10a is applied to the resist film on the wafer. It was also confirmed that the photosensitivity was suppressed.

Example (4-2)
(Light shielding film design)
As in Example (4-1), among the various MoSi-based film materials whose refractive index n and extinction coefficient k have been measured in advance, MoSi is formed on the light-shielding layer 11 as the film material of the light-shielding film 10. A MoSiON film (n = 2.3, k = 1.0) is selected as the film (n = 2.4, k = 1.9) and the surface antireflection layer 12, and the entire optical density (OD) of the light shielding film 10 is selected. ) And surface reflectance (R%). A graph plotting the calculated results is shown in FIG.

In this example (4-2), from the result of the optical simulation of FIG. 16, a film thickness of 33 nm and a film thickness of 6 nm are selected as the surface antireflection layer, respectively, and the optical density is 2.0 or more. The light shielding film 10 having a reflectance of 30% or less was designed.
Next, whether or not sufficient contrast can be obtained when a transfer mask is produced with a mask blank using the selected light-shielding film 10 and exposed and transferred to a resist on the wafer is shown in Example (4-1). As with, it was confirmed by optical simulation. The result is shown in FIG. From the results of FIG. 17, it was found that the contrast was as good as 0.8 or higher even at an optical density of 2.0.

  Next, in the mask blank using the selected light shielding film 10, whether or not the EMF bias was sufficiently reduced was confirmed by optical simulation as in Example (4-1). However, the thickness of the surface antireflection layer was fixed at 6 nm and optical simulation was performed. The result is shown in FIG. From the result of FIG. 18, it was found that when the total film thickness of the light shielding film 10 is 40 nm or less, the influence of the EMF effect can be greatly reduced as compared with the conventional light shielding film having a total film thickness of about 60 nm.

(Manufacture of mask blank)
In Example (4-2), a mask blank similar to Example (4-1) was produced, except that the light shielding film 10 was replaced with the light shielding film 10 designed from the result of the optical simulation of FIG.
In Example (4-2), a MoSiN film (light shielding layer 11) and a MoSiON film (surface antireflection layer 12) were formed as the light shielding film 10 on the translucent substrate 1, respectively.

Specifically, a DC magnetron sputtering apparatus is used, a target of Mo: Si = 21 atomic%: 79 atomic% is used, and a mixed gas atmosphere of Ar and N ₂ is composed of molybdenum, silicon, and nitrogen in a gas atmosphere. A film (Mo: 15 atomic%, Si: 56 atomic%, N: 29 atomic%) was formed to a thickness of 33 nm to form a MoSiN film (light shielding layer 11).
Next, using a target of Mo: Si = 4 atomic%: 96 atomic%, in a mixed gas atmosphere of Ar, O ₂ , N _2, and He, a film made of molybdenum, silicon, oxygen, and nitrogen (Mo: 3 atomic%, Si: 56 atomic%, O: 16 atomic%, N: 25 atomic%) was formed with a film thickness of 6 nm to form a MoSiON film (surface antireflection layer 12).
Next, the substrate was heated (annealed) at 450 ° C. for 30 minutes.

Refractive index n and extinction coefficient k were measured with respect to light shielding film 10 formed on translucent substrate 1 using an optical thin film characteristic measuring device n & k 1280 (manufactured by n & k Technology). As a result, this light-shielding film 10 was confirmed that the light-shielding layer 11 had n = 2.4 and k = 1.9, and the surface antireflection layer 12 had n = 2.3 and k = 1.0. It was. Moreover, the optical density (OD) and the surface reflectance were measured with respect to the light shielding film 10 with a spectrophotometer U-4100 (manufactured by Hitachi High-Technologies Corporation). As a result, it was confirmed that this light-shielding film 10 had an optical density of 2.0 with respect to ArF exposure light (wavelength 193 nm) and a surface reflectance of 26.7%. Further, when the optical density was measured after the auxiliary light shielding film 20 was formed, it was confirmed that the optical density with respect to ArF exposure light (wavelength 193 nm) was 2.8 in the laminated structure of the light shielding film 10 and the auxiliary light shielding film 20. It was.
As described above, a binary mask blank on which the auxiliary light shielding film 20 and the light shielding film 10 for ArF excimer laser exposure and single exposure were formed was obtained.

(Preparation of transfer mask)
Using the binary mask blank of this example (4-2), a binary transfer mask of this example (4-2) was produced in the same manner as in the above example (4-1).
Again, for the mask design pattern, prepare the transfer pattern generated by strict correction calculation by EMF simulation as before, and the transfer pattern generated by correction calculation by reducing the calculation load by using TMA simulation, etc. Each transfer pattern was drawn on the resist film 100 of the two binary mask blanks produced previously, and two binary transfer masks were produced.
When the transfer pattern was exposed and transferred to the resist film on the wafer with an exposure apparatus for each of the two binary transfer masks, both patterns could be transferred with high accuracy. It can be confirmed that the mask blank of this Example (4-2) can produce a transfer mask having sufficient transfer performance even with a transfer pattern generated by correction calculation using TMA simulation to reduce the calculation load. It was. In addition, even for a maximum of four times of overexposure due to leakage light to the outer peripheral region, the light shielding portion (light shielding band) 80 composed of the auxiliary light shielding film pattern 20b and the light shielding film pattern 10a is applied to the resist film on the wafer. It was also confirmed that the photosensitivity was suppressed.

Example (4-3)
(Light shielding film design)
As in Example (4-1), among the various MoSi based film materials whose refractive index n and extinction coefficient k have been measured in advance, MoSiN is used as the light shielding layer 11 as the film material of the light shielding film 10. A MoSiN film (n = 2.0, k = 0.9) is selected as the film (n = 1.8, k = 2.1) and the surface antireflection layer 12, and the entire optical density (OD) of the light shielding film 10 is obtained. ) And surface reflectance (R%). A graph plotting the calculated results is shown in FIG.

In this example (4-3), from the result of the optical simulation of FIG. 19, 30 nm is selected as the thickness of the light shielding layer 11 and 10 nm is selected as the surface antireflection layer, and the optical density is 2.0 or more. The light shielding film 10 having a reflectance of 20% or less was designed.
Next, whether or not sufficient contrast can be obtained when a transfer mask is produced with a mask blank using the selected light-shielding film 10 and exposed and transferred to a resist on the wafer is shown in Example (4-1). As with, it was confirmed by optical simulation. The result is shown in FIG. From the results of FIG. 20, it was found that the contrast was as good as 0.8 or higher even at an optical density of 2.0.

  Next, in the mask blank using the selected light shielding film 10, whether or not the EMF bias was sufficiently reduced was confirmed by optical simulation as in Example (4-1). However, the thickness of the surface antireflection layer was fixed at 10 nm and optical simulation was performed. The result is shown in FIG. From the results of FIG. 21, it was found that when the total film thickness of the light shielding film 10 is 40 nm or less, the influence of the EMF effect can be greatly reduced as compared with the conventional light shielding film having a total film thickness of about 60 nm.

(Manufacture of mask blank)
In Example (4-3), a mask blank similar to Example (4-1) was produced, except that the light shielding film 10 was replaced with the light shielding film 10 designed from the result of the optical simulation of FIG.
In Example (4-3), a MoSiN film (light shielding layer 11) and a MoSiN film (surface antireflection layer 12) were formed as the light shielding film 10 on the translucent substrate 1, respectively.

Specifically, using a DC magnetron sputtering apparatus, a film made of molybdenum, silicon, and nitrogen (Mo: 9 atomic%, Si: 64 atomic%, N: 27 atomic%) is formed with a film thickness of 30 nm, and a MoSiN film (Light shielding layer 11) was formed.
Next, using a DC magnetron sputtering apparatus, a film made of molybdenum, silicon, and nitrogen (Mo: 8 atomic%, Si: 48 atomic%, N: 44 atomic%) is formed to a thickness of 10 nm, and a MoSiN film (surface reflection) A prevention layer 12) was formed.

Refractive index n and extinction coefficient k were measured with respect to light shielding film 10 formed on translucent substrate 1 using an optical thin film characteristic measuring device n & k 1280 (manufactured by n & k Technology). As a result, this light-shielding film 10 was confirmed that the light-shielding layer 11 was n = 1.8 and k = 2.1, and the surface antireflection layer 12 was n = 2.0 and k = 0.9. It was. Moreover, the optical density (OD) and the surface reflectance were measured with respect to the light shielding film 10 with a spectrophotometer U-4100 (manufactured by Hitachi High-Technologies Corporation). As a result, it was confirmed that the light shielding film 10 had an optical density of 2.0 with respect to ArF exposure light (wavelength 193 nm) and a surface reflectance of 17.9%. Further, when the optical density was measured after the auxiliary light shielding film 20 was formed, it was confirmed that the optical density with respect to ArF exposure light (wavelength 193 nm) was 2.8 in the product structure of the light shielding film 10 and the auxiliary light shielding film 20. It was. Further, when the optical density was measured after the auxiliary light shielding film 20 was formed, it was confirmed that the optical density with respect to ArF exposure light (wavelength 193 nm) was 2.8 in the laminated structure of the light shielding film 10 and the auxiliary light shielding film 20. It was.
As described above, a binary mask blank on which the auxiliary light shielding film 20 and the light shielding film 10 for ArF excimer laser exposure and single exposure were formed was obtained.

(Preparation of transfer mask)
Using the binary mask blank of this example (4-3), a binary transfer mask of this example (4-3) was produced in the same manner as in the above example (4-1).
Again, for the mask design pattern, prepare the transfer pattern generated by strict correction calculation by EMF simulation as before, and the transfer pattern generated by correction calculation by reducing the calculation load by using TMA simulation, etc. Each transfer pattern was drawn on the resist film 100 of the two binary mask blanks produced previously, and two binary transfer masks were produced.
When the transfer pattern was exposed and transferred to the resist film on the wafer with an exposure apparatus for each of the two binary transfer masks, both patterns could be transferred with high accuracy. It can be confirmed that the mask blank of this example (4-3) can produce a transfer mask having a sufficient transfer performance even with a transfer pattern generated by a correction calculation with a light calculation load using TMA simulation. It was. In addition, even for a maximum of four times of overexposure due to leakage light to the outer peripheral region, the light shielding portion (light shielding band) 80 composed of the auxiliary light shielding film pattern 20b and the light shielding film pattern 10a is applied to the resist film on the wafer. It was also confirmed that the photosensitivity was suppressed.

Examples (4-4) to (4-6)
As shown in FIG. 2, the examples (4-4) to (4-6) are formed on the auxiliary light shielding film 20 by using the etching mask ( Hard mask) The same as in Examples (4-1) to (4-3) except that the film 30 and the adhesion improving layer 60 were formed.
In the embodiments of the embodiments (4-4) to (4-6), the auxiliary light shielding film is compared with the Cr-based auxiliary light shielding film 20 (also serving as an etching mask) of the embodiments (4-1) to (4-3). Since the etching mask film is divided as a dedicated film, the etching mask film 30 can be thinned, and the resist can be thinned.

Examples (4-7) to (4-9)
As shown in FIG. 3, the examples (4-7) to (4-9) are formed on the auxiliary light-shielding film 20 with the etching masks (1-7) to (1-9) shown in the examples (1-9). (Hard mask) The same as the embodiments (4-1) to (4-3) except that the film 30 and the second etching mask film 40 are formed.
In the embodiments of the embodiments (4-7) to (4-9), the adoption of the chromium-based second etching mask film 40 makes the comparison with the embodiments of the embodiments (4-4) to (4-6). The resist can be thinned and the adhesion of the resist is improved.

Examples (4-10) to (4-12)
In Examples (4-10) to (4-12), as shown in FIG. 4 and Examples (1-10) to Example (1-12), an etching stopper / mask layer 21 and an auxiliary light shielding layer 22 are formed. The same as in Examples (4-1) to (4-3) except that the auxiliary light-shielding film 20 was formed in a laminated structure and the adhesion improving layer 60 was formed thereon.
In the embodiments of the above Examples (4-10) to (4-12), the light-shielding film is compared with the Cr-based auxiliary light-shielding film 20 (also serving as an etching mask) of the above Examples (4-1) to (4-3). Thus, the etching stopper / mask layer 21 can be made thinner with respect to 10. Thereby, higher etching accuracy of the light shielding film 10 is obtained.
In the embodiments (4-10) to (4-12), compared with the Cr-based auxiliary light-shielding film 20 of the above-described Examples (4-1) to (4-3), compared with the same optical density, The auxiliary light shielding film 20 can be thinned. This thin auxiliary light-shielding film 20 enables the resist to be thinned as compared with the embodiments (4-1) to (4-3).

Examples (4-13) to (4-15)
In Examples (4-13) to (4-15), as shown in FIG. 5 and Examples (1-13) to (1-15), instead of the adhesion improving layer 60, an etching mask film 70 is used. Except that it was formed, it is the same as Examples (4-10) to (4-12).
In the embodiments of the embodiments (4-13) to (4-15), the use of the chromium-based etching mask film 70 allows the resist to be compared with the embodiments (4-10) to (4-12). The film thickness can be reduced and the adhesion of the resist is improved.

Examples (5-1) to (5-15)
In Examples (5-1) to (5-15), as shown in Examples (2-1) to (2-15), the optical density of the auxiliary light-shielding film 20 is 1.1, and is used for double exposure. Except that a binary mask blank is used, the same as in Examples (4-1) to (4-15).
In the embodiments of the embodiments (5-1) to (5-15), when a binary transfer mask set corresponding to double exposure is produced from two binary mask blanks, the maximum number of times is eight times due to light leaking to the outer peripheral region. With respect to the overexposure, the light-shielding portion (light-shielding band) 80 constituted by the auxiliary light-shielding film pattern 20b and the light-shielding film pattern 10a can suppress the exposure to the resist film on the wafer.

Example (6-1)
(Light shielding film design)
As in Example (4-1), among the various MoSi-based film materials whose refractive index n and extinction coefficient k have been measured in advance, MoSi is formed on the light-shielding layer 11 as the film material of the light-shielding film 10. A MoSiON film (n = 2.1, k = 0.6) is selected as the film (n = 2.4, k = 2.9) and the surface antireflection layer 12, and the entire optical density (OD) of the light shielding film 10 is obtained. ) And surface reflectance (R%). A graph plotting the calculated results is shown in FIG.

In this example (6-1), from the result of the optical simulation of FIG. 22, the film thickness of the light shielding layer 11 is selected to be 26 nm, and the film thickness is 14 nm as the surface antireflection layer, and the optical density is 2.3 or more. The light shielding film 10 having a reflectance of 20% or less was designed.
Next, whether or not sufficient contrast can be obtained when a transfer mask is produced with a mask blank using the selected light-shielding film 10 and exposed and transferred to a resist on the wafer is shown in Example (4-1). As with, it was confirmed by optical simulation. As a result, it was found that even if the optical density was 2.3, the contrast was as good as 0.8 or more.

  Next, in the mask blank using the selected light shielding film 10, whether or not the EMF bias was sufficiently reduced was confirmed by optical simulation as in Example (4-1). However, the thickness of the surface antireflection layer was fixed at 14 nm, and optical simulation was performed. The result is shown in FIG. From the result of FIG. 23, it was found that when the total film thickness of the light shielding film 10 is 40 nm or less, the influence of the EMF effect can be greatly reduced as compared with the conventional light shielding film having a total film thickness of about 60 nm.

(Manufacture of mask blank)
In this example (6-1), the mask used for double exposure is the same as that of the example (3-1) except that the light shielding film 10 is replaced with the light shielding film 10 designed from the result of the optical simulation of FIG. A blank was produced.
In Example (6-1), a MoSi film (light shielding layer 11) and a MoSiON film (surface antireflection layer 12) were formed as the light shielding film 10 on the translucent substrate 1, respectively.

Specifically, a MoSi film (light shielding layer 11) having a film thickness of 26 nm was formed under the same film formation conditions as in Example (4-1).
Next, using a target of Mo: Si = 4 atomic%: 96 atomic%, in a mixed gas atmosphere of Ar, O ₂ , N _2, and He, a film made of molybdenum, silicon, oxygen, and nitrogen (Mo: 2 atomic%, Si: 39 atomic%, O: 18 atomic%, and N: 41 atomic%) were formed with a film thickness of 14 nm to form a MoSiON film (surface antireflection layer 12).
Next, the substrate was heated (annealed) at 450 ° C. for 30 minutes.

Refractive index n and extinction coefficient k were measured with respect to light shielding film 10 formed on translucent substrate 1 using an optical thin film characteristic measuring device n & k 1280 (manufactured by n & k Technology). As a result, this light-shielding film 10 was confirmed that the light-shielding layer 11 had n = 2.4 and k = 2.9, and the surface antireflection layer 12 had n = 2.1 and k = 0.6. It was. Moreover, the optical density (OD) and the surface reflectance were measured with respect to the light shielding film 10 with a spectrophotometer U-4100 (manufactured by Hitachi High-Technologies Corporation). As a result, it was confirmed that the light shielding film 10 had an optical density of 2.3 with respect to ArF exposure light (wavelength 193 nm) and a surface reflectance of 9.4%. Further, when the optical density was measured after the auxiliary light shielding film 20 was formed, it was confirmed that the optical density with respect to ArF exposure light (wavelength 193 nm) was 3.1 in the laminated structure of the light shielding film 10 and the auxiliary light shielding film 20. It was.
As described above, a binary mask blank in which the auxiliary light shielding film 20 and the light shielding film 10 for ArF excimer laser exposure and double exposure were formed was obtained.

(Preparation of transfer mask)
Using the binary mask blank of this example (6-1), a set of a binary transfer mask for double exposure of this example (6-1) was produced in the same manner as in the above example (3-1). .
Here, a set of transfer patterns generated by rigorous correction calculation using EMF simulation as compared to a set of mask design patterns divided into two by applying double patterning technology to a design pattern of DRAM hp32 nm generation, and TMA A set of transfer patterns generated by correction calculation is prepared by reducing the calculation load by using a simulation or the like, and each set of transfer patterns is drawn on the resist film 100 of the four binary masks prepared previously. Each set of binary transfer masks was prepared.
When the transfer pattern was exposed and transferred to the resist film on the wafer with an exposure apparatus for each set of binary transfer masks produced, both DRAM hp32 nm generation patterns could be transferred with high precision. It can be confirmed that the mask blank of this Example (6-1) can produce a transfer mask having sufficient transfer performance even with a transfer pattern generated by correction calculation using TMA simulation to reduce the calculation load. It was. In addition, even for a maximum of eight times of overexposure by leakage light to the outer peripheral region, the light shielding portion (light shielding band) 80 constituted by the auxiliary light shielding film pattern 20b and the light shielding film pattern 10a is applied to the resist film on the wafer. It was also confirmed that the photosensitivity was suppressed.

Example (6-2)
(Light shielding film design)
As in Example (4-1), among various Ta-based film materials whose refractive index n and extinction coefficient k have been measured in advance, TaN is applied to the light shielding layer 11 as the film material of the light shielding film 10. A TaO film (n = 2.2, k = 1.1) is selected as the film (n = 1.8, k = 2.4) and the surface antireflection layer 12, and the entire optical density (OD) of the light shielding film 10 is obtained. ) And surface reflectance (R%). A graph in which the calculated results are plotted is shown in FIG.

In this example (6-2), from the result of the optical simulation of FIG. 24, 33 nm is selected as the thickness of the light shielding layer 11 and 6 nm is selected as the surface antireflection layer, and the optical density is 2.3 or more. The light shielding film 10 having a reflectance of 30% or less was designed.
Next, whether or not sufficient contrast can be obtained when a transfer mask is produced with a mask blank using the selected light-shielding film 10 and exposed and transferred to a resist on the wafer is shown in Example (4-1). As with, it was confirmed by optical simulation. The result is shown in FIG. From the results of FIG. 25, it was found that the contrast was as good as 0.8 or more even at an optical density of 2.3.

  Next, in the mask blank using the selected light shielding film 10, whether or not the EMF bias was sufficiently reduced was confirmed by optical simulation as in Example (4-1). However, the thickness of the surface antireflection layer was fixed at 6 nm and optical simulation was performed. The result is shown in FIG. From the results of FIG. 26, it was found that when the total film thickness of the light shielding film 10 is 40 nm or less, the influence of the EMF effect can be greatly reduced as compared with the conventional light shielding film having a total film thickness of about 60 nm.

(Manufacture of mask blank)
In Example (6-2), a mask blank similar to Example (6-1) was produced, except that the light shielding film 10 was replaced with the light shielding film 10 designed from the result of the optical simulation of FIG.
In Example (6-2), a TaN film (light shielding layer 11) and a TaO film (surface antireflection layer 12) were formed as the light shielding film 10 on the translucent substrate 1, respectively.

Specifically, a film made of tantalum nitride (TaN) (Ta: 93 atomic%, N: 7 atomic%) in a mixed gas atmosphere of Ar and N ₂ using a DC magnetron sputtering apparatus and a Ta target. The light shielding layer 11 was formed with a film thickness of 33 nm.
Next, using a Ta target, a film made of tantalum oxide (TaO) (Ta: 42 atomic%, O: 58 atomic%) is formed with a film thickness of 6 nm in a mixed gas atmosphere of Ar and O ₂ to prevent surface reflection. Layer 12 was formed.

Refractive index n and extinction coefficient k were measured with respect to light shielding film 10 formed on translucent substrate 1 using an optical thin film characteristic measuring device n & k 1280 (manufactured by n & k Technology). As a result, this light-shielding film 10 was confirmed that the light-shielding layer 11 was n = 1.8 and k = 2.4, and the surface antireflection layer 12 was n = 2.2 and k = 1.1. It was. Moreover, the optical density (OD) and the surface reflectance were measured with respect to the light shielding film 10 with a spectrophotometer U-4100 (manufactured by Hitachi High-Technologies Corporation). As a result, it was confirmed that the light shielding film 10 had an optical density of 2.3 with respect to ArF exposure light (wavelength 193 nm) and a surface reflectance of 27.9%. Further, when the optical density was measured after the auxiliary light shielding film 20 was formed, it was confirmed that the optical density with respect to ArF exposure light (wavelength 193 nm) was 3.1 in the laminated structure of the light shielding film 10 and the auxiliary light shielding film 20. It was.
As described above, a binary mask blank in which the auxiliary light shielding film 20 and the light shielding film 10 for ArF excimer laser exposure and double exposure were formed was obtained.

(Preparation of transfer mask)
Using the binary mask blank of this example (6-2), a binary transfer mask of this example (6-2) was produced in the same manner as in the above example (1-3).
Here, a set of transfer patterns generated by rigorous correction calculation using EMF simulation as compared to a set of mask design patterns divided into two by applying double patterning technology to a design pattern of DRAM hp32 nm generation, and TMA A set of transfer patterns generated by correction calculation is prepared by reducing the calculation load by using a simulation or the like, and each set of transfer patterns is drawn on the resist film 100 of the four binary masks prepared previously. Each set of binary transfer masks was prepared.
When the transfer pattern was exposed and transferred to the resist film on the wafer with an exposure apparatus for each set of binary transfer masks produced, both DRAM hp32 nm generation patterns could be transferred with high precision. It can be confirmed that the mask blank of this Example (6-2) can produce a transfer mask having sufficient transfer performance even with a transfer pattern generated by correction calculation using TMA simulation to reduce the calculation load. It was. In addition, even for a maximum of eight times of overexposure by leakage light to the outer peripheral region, the light shielding portion (light shielding band) 80 constituted by the auxiliary light shielding film pattern 20b and the light shielding film pattern 10a is applied to the resist film on the wafer. It was also confirmed that the photosensitivity was suppressed.

Example (6-3), (6-4)
In Examples (6-3) and (6-4), the etching masks (1-4) and (1-6) shown in Example (1-6) are formed on the auxiliary light shielding film 20 as shown in FIG. Hard mask) The same as in Examples (6-1) and (6-2) except that the film 30 and the adhesion improving layer 60 were formed.
In the embodiments (6-3) and (6-4), the auxiliary light-shielding film as compared with the Cr-based auxiliary light-shielding film 20 (also serving as an etching mask) of Examples (6-1) and (6-2). Since the etching mask film is divided as a dedicated film, the etching mask film 30 can be thinned, and the resist can be thinned.

Example (6-5), (6-6)
In Examples (6-5) and (6-6), as shown in FIG. 3, the etching masks (1-7) and (1-9) shown in Example (1-9) are formed on the auxiliary light shielding film 20. (Hard mask) The same as in Examples (6-1) and (6-2) except that the film 30 and the second etching mask film 40 are formed.
In the embodiments (6-5) and (6-6), the adoption of the chromium-based second etching mask film 40 makes the embodiment (6-3) and (6-4) different from the embodiments described above. The resist can be thinned and the adhesion of the resist is improved.

Example (6-7), (6-8)
In Examples (6-7) and (6-8), as shown in FIG. 4, Example (1-10), and Example (1-12), an etching stopper / mask layer 21 and an auxiliary light shielding layer 22 are formed. The same as in Examples (6-1) and (6-2) except that the auxiliary light-shielding film 20 was formed in a laminated structure and the adhesion improving layer 60 was formed thereon.
In the embodiments (6-7) and (6-8), the light shielding film is compared to the Cr-based auxiliary light shielding film 20 (also serving as an etching mask) of the above embodiments (6-1) and (6-2). Thus, the etching stopper / mask layer 21 can be made thinner with respect to 10. Thereby, higher etching accuracy of the light shielding film 10 is obtained.
In the embodiments of Examples (6-7) and (6-8), compared with the Cr-based auxiliary light shielding film 20 of Examples (6-1) and (6-2), compared with the same optical density, The auxiliary light shielding film 20 can be thinned. This thin auxiliary light-shielding film 20 makes it possible to reduce the thickness of the resist as compared with the embodiments (6-1) and (6-2).

Example (6-9), (6-10)
In Examples (6-9) and (6-10), as shown in FIG. 5 and Examples (1-13) and (1-15), instead of the adhesion improving layer 60, an etching mask film 70 is used. Except for the formation, it is the same as Examples (6-7) and (6-8).
In the embodiments (6-9) and (6-10), the use of the chromium-based etching mask film 70 allows the resist to be used in comparison with the embodiments (6-7) and (6-8). The film thickness can be reduced and the adhesion of the resist is improved.

  As mentioned above, although this invention was demonstrated using embodiment and an Example, the technical scope of this invention is not limited to the range as described in the said embodiment and Example. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiments and examples. It is apparent from the description of the scope of claims that embodiments with such changes or improvements can be included in the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Translucent substrate 10 Light shielding film 11 Light shielding layer 12 Surface antireflection layer 20 Auxiliary light shielding film 30 Etching mask film 40 Second etching mask film 50 Etching stopper / mask layer 60 Adhesion improving layer 70 Etching mask film 100 Resist film

Claims (9)

A mask blank used for producing a transfer mask to which ArF exposure light is applied,
A light shielding film having a laminated structure of a light shielding layer and a surface antireflection layer formed on a light transmissive substrate, and an auxiliary light shielding film formed above the light shielding film,
The light shielding film has a film thickness of 40 nm or less and an optical density with respect to exposure light of 2.0 or more and 2.7 or less,
The light shielding layer has a thickness of 15 nm or more and 35 nm or less,
A mask blank having an optical density of 2.8 or more with respect to exposure light in a laminated structure of the light shielding film and the auxiliary light shielding film.   The mask blank according to claim 1, wherein the surface antireflection layer has a film thickness of 5 nm or more and 20 nm or less, and a surface reflectance for exposure light of 30% or less.   The mask blank according to claim 1, wherein an optical density with respect to exposure light in the laminated structure of the light shielding film and the auxiliary light shielding film is 3.1 or more. The mask blank according to claim 1, wherein the light shielding layer contains 90% or more of transition metal silicide. 5. The mask blank according to claim 4, wherein the transition metal silicide in the light shielding layer is molybdenum silicide, and the molybdenum content is 9 atomic% or more and 40 atomic% or less. 6. The mask blank according to claim 1, wherein the surface antireflection layer is made of a material mainly composed of a transition metal silicide. The mask blank according to any one of claims 1 to 6, wherein the auxiliary light shielding film has resistance to an etching gas used when the light shielding film is etched. The auxiliary light-shielding film contains at least one of nitrogen and oxygen in chromium, the chromium content in the film is 50 atomic% or less, and the film thickness is 20 nm or more. The mask blank according to any one of claims 1 to 7. A transfer mask produced using the mask blank according to claim 1.